Dioscorea sativa, L.? vulgo “Alapa.”
JUNCACEÆ.
Flagellaria indica, L. var.
TACCACEÆ.
Tacca pinnatifida, Forst.: vulgo “Mamago.” The natives do not appear
to make use of the arrowroot-like starch obtainable from the tubers.
PANDANACEÆ.
Pandanacea: genus novum,[434](♀ flowers only and leaf collected).
The only locality where I found it was the summit of Faro Island,
where it grows to a height of fifty feet, and has a long white
female branching spadix, three to four feet in length. The same, or
a near ally, was obtained by Signor Beccari in Jobi Island, off New
Guinea. (_Vide_ page 289.)
[434] I learn from Professor Oliver that Count Solins confirms the
generic distinctness.
The natives distinguish several species of Pandanus trees, of which
I was only able to obtain the fruit. The “darashi” “sararang,” and
“pota,” grow at the coast, and have a height of from thirty to forty
feet. The “darashi” has narrow leaves, and, if the ground is not
rocky, aerial roots are often absent: the fruit is smaller than that
of the two other littoral pandanus trees. The “sararang” has broad
leaves, and always aerial roots: the fruit is often more than a foot
in diameter. The “pota” has broad leaves, with contracted acuminate
apices, two inches long: the fruit is about a foot in diameter:
aerial roots are always present, and rise often fifteen feet from
the ground. The segments of these pandanus trees all contain edible
kernels. The broad leaves of the “pota” are employed in making
mats. . . . There is another pandanus tree, the “samala” of the
natives, which often grows away from the coast, as on the banks of
streams: it has an erect, stout trunk, thirty-five to forty feet
high, without aerial roots, and does not branch.
Freycinetia sp. . .
Freycinetia sp. . .
Nipa fruticans.
PALMACEÆ.
Cyrtostachys sp. . . vulgo “Sensisi.” Growing up to fifty feet high
on the banks of streams.
Palmacea dub. (cf. Drymophloeus): vulgo “Kisu.” Growing seventy to
eighty feet high. The tough sheathing at the bases of the branches
is employed for making the native dishes.
Pinanga sp. . . vulgo “Kisu”: conf. the “Kisu” above. Growing up to
seventy or eighty feet high.
Caryota sp. . . vulgo “Eala.” Growing up to fifty feet high.
Licuala sp. . . vulgo “Firo.” Grows up to thirty-five or forty feet
in height. More common on volcanic soils. Absent from Treasury
Island, with the exception of one imported tree. Said to be very
numerous in the large adjacent island of Bougainville, the leaves
being there used in making conical hats.
Palmacea dub.: vulgo “Poamau.” Grows up to seventy or eighty feet
high. Its fruit, which is eaten by the women, is said to have a
stimulant effect like the betel-nut. Its wood supplies the material
for spears.
Areca sp. . . vulgo “Momo.” Grows up to thirty-five or forty feet
high. Small fruits (½ inch) sessile on a branching stalk.
Areca sp. . . vulgo “Niga-torulo,” or “Torulo.” Grows up to
thirty-five or forty feet high. Fruits larger (1-1½ inch) sessile,
and gathered thickly together on an undivided stalk.
Areca sp. . . vulgo “Niga-solu.” Grows up to fifty feet high. Fruits
(1-1½ inch) sessile, gathered thickly together on an undivided
stalk.
[_Note._--The three kinds of areca palms just mentioned are very
common on the low ground at the foot of hills. They all have a
general resemblance, and their fruits are often chewed in lieu of
“betel-nuts.” They are distinguished from each other readily by the
size and mode of attachment of the fruits, and by the number of ribs
on the lateral pinnæ.]
Areca sp. . . vulgo “Poamau.” Growing up to eighty feet high.
Areca sp. . . vulgo “Au-Au.” Grows up to twelve feet high. Aerial
roots rising from stem 1½ feet above the ground.
Areca sp. . . vulgo “Olega.” The betel-nut palm of the Solomon
Islands. Planted by the natives in the vicinity of their villages.
Height up to thirty feet.
Sagus sp. . . vulgo “Bia,” “Nami.” Height up to sixty feet. Dry
situations.
AROIDEÆ.
Schizmatoglottis sp. . . vulgo “Kuraka.” Growing wild along the
banks of streams. The natives make a savoury vegetable broth of the
leaves and unopened spathes.
Epipremnum cf. E. mirabile, Sch. Found on trees.
Scindapsus sp. . . vulgo “Kurricolo.” Grows on sandy soil near the
coast. Pothos?
CYPERACEÆ.
Cyperus (Mariscus phleoides, Nees). Height two to two and a half
feet.
Cyperus canescens, Vahl. Height two feet.
Cyperus (Mariscus umbellatus, V.). Height one foot.
Kyllinga monocephala, Rottb. Six to eight inches high.
Mapania sp. . . Three feet high.
GRAMINEÆ.
Eleusine indica, Gærtn.
Panicum (Digitaria) sanguinale, L.
„ radicans, Retz?
„ carinatum, Presl.
„ neurodes, Sch.
Pennisetum (Gymnothrix Thouarsii Beauv.?). Also
Pennisetum macrostachys, Trin. (fide F. v. Mueller): vulgo “Orsopa.”
Growing in waste ground of plantations to a height of eight or nine
feet.
Coix Lachryma, L.: vulgo “Ken-ken.” The natives do not appear to
make use of the seeds as beads. Growing in the waste ground of
plantations.
Pollinia obtusa, Munro? Schizostachyum?? A bamboo usually found at
elevations of 1000 or 1100 feet above the sea. The canes grow to a
length of thirty-five to forty feet, and are used as fishing-rods.
MUSCI.
Octoblepharum (Leucophanes) squarrosum, Brid.
HEPATICÆ.
Marchantia linearis, L. and L.?
FUNGI.
Agaricus (perhaps mollic, Schff.).
„ (Inocybe) maritimus, Fr.
Hygrophorus metapodius, Fr. prox.
Lentinus submembranaceus, B.
„ dactyliophorus, Lev.
„ velutinus, Fr.
Polyporus (Mes.) xanthopus, Fr.
„ (Pleur.) affinis, Nees.
„ (Pleur.) luteus, Nees.
„ (Pleur.) lucidus, Fr.
„ (Placo.) australis Fr.
Hexagona apiaria, Fr.
„ similis, B.
Cladoderris dendritica, Fr.
Thelephora lamellata, B.
Hirneola auricula-judæ, Fr.
Lycoperdon gemmatum, Fr.
Bovista sp. . . (uncertain).
Wynnea macrotis, Berk.
* * * * *
_The Flotation of Fruits in Sea-Water._--I made a few experiments on the
fruits of this region, the results of which I here append. The fruits
were all ripe and not dried.
(1.) Fruits that _float_ in sea-water.[435]
Cocos nucifera
Areca catechu (Betel-nut).
Cycas circinalis.[436]
Pandanus (three littoral species).
Nipa fruticans.
Barringtonia speciosa.
Calophyllum inophyllum.
Calophyllum sp. (katari).
Ochrosia parviflora.
Heritiera littoralis.
Cerbera odollam.
Harpullia cupanioides.
Myristica sp. (ito-ito).
Riedelia curviflora.?
Thespesia populnea.
Gomphandra sp. (ningilo).
[435] The following fruits and seeds, taken from my dried collection
of plants, float in sea-water. I did not experiment on them in the
green condition. . . . Pongamia glabra: Coix Lachryma: Scævola
Kœnigii: Tournefortia argentea.
[436] Out of ten fruits experimented on, only one floated.
(2.) Fruits that _sink_ in sea-water.
Parinarium laurinum.[437]
Licuala sp. (firo).
Areca sp. (torulo).
Areca sp. (momo).
Caryota sp. (eala).
[437] This tree is widely distributed throughout the group, which
may be due to the circumstance of its resin being generally employed
in caulking canoes.
* * * * *
_The weeds, rubbish-plants, and shrubs, commonly found in old clearings
and in the waste-ground of the cultivated patches in Bougainville
Straits._
One of the commonest plants in the islands of Bougainville Straits is
the _Eranthemum variabile_, which is frequently found growing at the
sides of the paths. The spurges, _Euphorbia pilulifera_ and _E. Atoto_,
are usually found in the waste-ground around villages. In the cultivated
patches clumps of the handsome flowering reed, _Pennisetum macrostachys_
(“orsopa”), which grows to a height of nine or ten feet, are often
conspicuous. In one place may be seen the tall shrub, _Kleinhovia
Hospita_ (“lafai”), the inflated fruits of which are eaten by the
cockatoos. In another place the botanist may recognise the _Canna
indica_ (Indian Shot: “sati”), and near by perhaps _Coix Lachryma_
(Job’s tears: “ken-ken”), both of which plants have been probably
introduced originally from the Malay Archipelago. Solomon Islanders
occasionally wear the seeds of _Coix Lachryma_ as a personal ornament.
They are also used for this purpose by the Admiralty Islanders, and by
the natives of some parts of New Guinea. Scented labiate plants are very
frequent in the waste-ground of the plantations, and the natives are
fond of wearing them in their armlets. Amongst them I may mention
_Moschosma polystachyum_ (“pipituan”) and _Ocymum sanctum_ (“kiramma”).
The “luk-a-luk” (_Evodia hortensis_), which is a favourite scented
plant, is commonly found in the same situations. The tiny plant, _Oxalis
corniculata_, may clothe a bare patch of ground; whilst in another part
of the plantation, _Commelyna nudiflora_ may similarly be observed.
Numerous composite plants, such as _Vernonia cinerea_, _Adenostemma
viscosum_, etc., form a conspicuous feature among the rubbish-plants in
these cultivated patches. The _Codiæum variegatum_ (“tiatakush”), with
its very singularly-shaped leaves, is also to be seen: and, amongst
other plants, I should refer to _Solanum vitiense_ and _Crotalaria
quinquefolia_. Tall sedges, such as _Cyperus canescens_ and _Mariscus
phleoides_, are to be commonly observed. Lastly, I should notice two
small scitamineous plants, the “nakia,” a wild ginger, and the “temuli,”
the root of which has medicinal properties, whilst its yellow juice is
used for staining purposes.
_A species of Pachyma??_
Whilst at the island of Santa Anna in October, 1882, my attention was
directed by Mr. William Macdonald and Mr. Heughan to a curious vegetable
substance, not unlike a yam in appearance, which is found _lying loose
on the soil_. The specimens I obtained varied between one and five
pounds in weight, but much larger examples have been obtained. The
interior of the substance is white in colour, and sometimes has a waxy
look. A large slab which had been whittled out by a native resembled a
cake of compressed flour. There were many curious speculations as to the
nature of these growths. In the estimation of the inhabitants of the
island, they are poisonous, and they have received from them the name of
“testes diaboli;” but I could gather but little information from the
natives on the subject except to the effect that they are also commonly
found on St. Christoval.[438] However, some time later I was informed by
Mr. Stephens of Ugi that some mushroom-like growths were borne by a
specimen that he kept, which after a few weeks fell away. I subsequently
gave some of these singular masses to Mr. Charles Moore, the Director of
the Sydney Botanic Gardens.
[438] In the event of it proving edible, Mr. Heughan cooked a
specimen, but only a tasteless substance resulted.
Three years passed away and I had almost forgotten about the matter,
when I accidentally came upon some substances, closely resembling these
masses, which are exhibited in the Botanical Department of the British
Museum. They are labelled _Pachyma Cocos_ (Fries) from China. On my
asking Mr. George Murray concerning their nature, I was pleased to learn
that he had been taking a special interest in these growths; and he
showed me a specimen obtained by the Rev. Mr. Whitmee in Samoa, from
which a funnel-shaped fungus, about six inches high, was growing. This
specimen was very similar to those of the Solomon Islands.
Very recently, Mr. G. Murray has embodied the results of his
investigations of these growths in a short paper read before the Linnean
Society, in which Mr. Whitmee’s specimen is figured (Trans. Linn. Soc.,
2nd ser. Bot., vol. ii., part 11). From this source I learn that
Rumphius was the first to describe these tuberous masses and their
associated fungi from Amboina. The former, which he named _Tuber
regium_, were stated to afford remedies useful in diarrhœa, fevers, &c.
The fungi were said to shoot out from them during showers of warm rain
on a fine day, or when there was thunder in the air. From the
description and illustration given by Rumphius, Mr. Fries regarded the
growth as a fungus belonging to the genus _Lentinus_, springing from a
_Pachyma_ (of which the Indian Bread of North America, _Pachyma cocos_,
is an example). Strange to say, however, these tubers, which are found
also in China and other parts of the world, have never been found with a
fungus attached since the time of Rumphius. Mr. Whitmee’s specimen,
therefore, had considerable interest. It is shown by Mr. Murray to
correspond strikingly with _Tuber regium_ and to have the structure of a
true “sclerotium” (not of _Pachyma_), with a fungus of a species of
_Lentinus_ growing from it. All the facts go to prove that the fungus
and the tuberous mass do not form part of the same growth, but are
distinct organisms. A spore having germinated on the surface of the
mass, its mycelium penetrates the interior, and becoming perennial,
produces successive crops of fungi.
Residents in the Indian Archipelago and in the Pacific Islands might
throw considerable light on the subject of these growths by careful
notes and collections. It is important to discover the origin of the
tuberous mass which becomes, so to speak, a convenient nidus for the
fungus. How do such masses perpetuate themselves? A considerable number
should be kept under observation, and the mode of appearance of the
fungus carefully noticed. Experiments might be made with the spores of
the fungus by dusting them over the surface of the masses. Such notes
and collections should be forwarded to Mr. Murray, at the British Museum
of Natural History.
CHAPTER XIV.
REPTILES AND BATRACHIANS.
IN a memoir on the Reptiles and Batrachians of the Solomon Islands,
which was read before the Zoological Society, on May 6th, 1884,[439] Mr.
Boulenger remarked that very little was known about the herpetology of
these islands until two important collections, which I sent to the
British Museum in 1883 and 1884, brought to light several new and
interesting forms, such as could hardly have been expected from this
region. “The position of this group of islands on the limits of two
great zoological districts,”--this author proceeded to observe--“renders
the study of its fauna of special interest, as it is the point where
many of the Papuasian and Polynesian forms intermingle. Curiously, all
the Batrachians belong to species not hitherto found elsewhere, and one
of them is even so strongly modified as to be the type of a distinct
family.”
[439] Published in the Transactions of the Society; vol. xii., part
i., 1886. The diagnoses of most of the new species in my collections
were given in the Proceedings for 1884: p. 210. Vide also “Annals
and Magazine of Natural History” (5) xii., 1883.
According to Mr. Boulenger, the Reptiles may be grouped under four
headings, viz.:--
1. Species belonging to both the Papuasian and Polynesian districts.
2. Indo-Malayan or Papuasian species, not extending further east or
south-east.
3. Polynesian species, not extending further north and west than New
Ireland.
4. Species not hitherto found elsewhere than in the Solomons (and New
Ireland.)
1
Gymnodactylus pelagicus
Gehyra oceanica
Mabuia cyanura
Platurus fasciatus.
2
Crocodilus porosus
Gecko vittatus
Varanus indicus
Keneuxia smaragdina
Enygrus carinatus
Dipsas irregularis.
3
Gonyocephalus godeffroyi
Mabuia carteretii
„ nigra
Enygrus bibronii.
4
Lepidodactylus guppyi, _n. sp._
Lipinia anolis, _n. sp._
Corucia zebrata
Dendrophis solomonis
Hoplocephalus par, _n. sp._
All of these 19 Reptiles were included in my collection, with the
exception of _Corucia zebrata_, which, however, came under my
observation. I will now proceed to refer more particularly to the
Reptile-fauna of this region.
CROCODILES.--The species of Crocodile (_Crocodilus porosus_, Schneid),
which is so common in the Solomon Group, ranges from India and South
China through the Malay Archipelago and Papuan Islands to North
Australia. In these islands crocodiles appear to frequent in greatest
numbers the swamps and sandy shores of uninhabited coral islands, such
as those of the Three Sisters, and the coasts of the larger islands in
the vicinity of the mouths of the streams and rivers. I frequently
surprised them basking on the sand under the shade of a tree. On one
occasion I was standing on the spreading roots of a tree that were
exposed on the beach, when one of these reptiles darted out from under
my feet and dived into the sea. Of the marks that they make on the sand
when lying at rest, an oblong shallow impression corresponding to the
head, and a curved well-defined grove caused by the tail are alone
specially recognisable. When they are not alarmed and move leisurely
along, they leave a double row of footprints on the sand, with a narrow
median furrow produced by the weight of the tail; but when they have
been disturbed and make a rush to escape, they raise their tail and
leave only the tracks of their feet on the sand. These crocodiles are
equally at home in salt and fresh water. I have frequently passed them
in my Rob Roy canoe when they have been floating as though asleep at the
surface of the sea; and it was always in the sea that they found a
refuge when my little craft intruded itself within their haunts. They
came under my notice in the fresh-water lakes of Santa Anna and Stirling
Island, and in the lower courses of the streams in several localities.
They are apparently in no uncongenial conditions in the salt-water
lagoon of Eddystone Island, although its waters receive the hot
sulphureous vapours of submerged fumaroles.
These crocodiles do not apparently attain a greater length than 12 or 13
feet. Mr. Sproul shot one at Santa Anna which measured 9½ feet. A female
that I shot in the Shortland Islands, measured 11 feet. One of the
seamen of the “Lark,” named Prior, obtained from the natives the skull
of a rather larger specimen. Out of half-a-dozen individuals seen on the
Three Sisters, not one measured more than 7 or 8 feet.[440] Mr. Bateman,
a trader resident at Ugi, told me that at Wano on the St. Christoval
coast he saw a very large crocodile which, from his description, appears
to have been twice as long as any that I saw. It was, however, dusk at
the time; and in connection with this circumstance I should add that I
have found actual measurement to reduce the apparent length of a
crocodile from 14 to 11 feet.
[440] A skull given to me by Mr. Nisbet, the government-agent of the
“Redcoat,” at Ugi, was 12 inches long. It was obtained from the
natives of Guadalcanar.
Natives are rarely attacked by these reptiles, and they show little or
no fear of them. I have seen a full-grown crocodile dart under a line of
swimmers without causing any dismay. Of the numbers I saw, all were but
too anxious to get out of my way; and their cowardly nature is well
shown in the account of my capture of a specimen which is given below.
However, I came upon a man of Santa Anna who had had his leg broken by
one of these reptiles. The natives of Rubiana hold the crocodile in
veneration and work without fear in the places which it frequents. They
believe that only faithless wives are seized and carried off by the
monster. Pigs are occasionally the prey of the crocodile; but its usual
diet appears to be opossums (_Cusci_), large lacertilians, and fish.
The following account of the capture of a crocodile may interest some of
my readers. It was effected by no more formidable weapons than by a
number of long staves and a small “bull-dog” revolver. Accompanied by
six natives I was making the ascent of a large stream on the north-west
side of Alu, when some of my companions espied a large crocodile at the
bottom of a deep pool about 200 yards from the mouth of the stream. In
setting to work to effect its capture my men proceeded very methodically
to work, and evidently knew the tactics which the creature would employ.
Standing in the water just below the pool, we stood awaiting the descent
of the crocodile down the stream, whilst one of the natives was rousing
it up with a long pole to make it leave its hiding-place. After a little
time it began to get uneasy, and leaving the pool began to descend the
stream. Where we were standing, the stream was only knee-deep, and as
the reptile passed us in the shallow water some natives hit it on the
head with their poles, whilst others hurled their poles sharpened at the
ends, striking it in several places, and I planted a bullet behind its
neck. The creature showed no fight and immediately hid itself in the
pools near the mouth of the stream. During two hours, after we had been
driving it from one pool to another by means of our pointed poles and
staves, we seemed no nearer to its capture. At length there was a loud
out-cry from the natives. The crocodile was making a final rush for life
to cross the bar at the mouth of the stream and escape into the sea. We
all followed, some in the canoe and some through the water; and for a
short time I thought that the creature would escape. But being a little
disabled by our previous attacks, its progress across the bar was
somewhat checked; and the foremost of my men caught hold of its tail
just as it was getting into deep water. Very quickly we all came up, and
assisted in drawing it high and dry on the beach; and whilst two of our
number kept hold of its tail, the remainder belaboured its neck with
rocks and sticks until it died.[441] Its length proved to be 11 feet.
Throughout the whole chase the reptile made no outcry, and even when we
were belabouring it to death it only gave a kind of growl. In its
stomach I found a large quantity of partially digested food with the
remains of an opossum (_Cuscus_) and a large lizard 1½ feet long
(probably _Corucia zebrata_). It was a female, and, in the oviduct I
came upon an egg, which my natives appropriated, saying that it was very
good food; but they do not usually eat the flesh. I was unable from want
of space to keep more than the head of the animal, which I cut off and
carried back in my canoe to the ship. The skull is now in the British
Museum.
[441] An illustration in Mr. Bates’ “Naturalist on the Amazons”
represents a very similar scene.
LIZARDS. The Lacertilians are well represented in these islands. Those
at present described are given in the subjoined list.
_Geckonidæ_
Gymnodactylus pelagicus
Gehyra oceanica
Lepidodactylus guppyi. _n. sp._
Gecko vittatus
„ var. bivittatus.
_Agamidæ_
Gonyocephalus godeffroyi.
_Varanidæ_
Varanus indicus.
_Scincidæ_
Mabuia carteretii
„ cyanura
„ nigra
Keneuxia smaragdina
Lipinia anolis _n. sp._
Corucia zebrata.
The lizards, which most frequently meet the eyes of the visitors in the
vicinity of the beaches, are the two skinks, _Mabuia nigra_ and
_cyanura_. As a rule those species that are common at the coast have a
wide range, extending either into Polynesia or Papuasia or into both
these regions (_vide_ page 307). The species peculiar to these islands
came less frequently under my observation. Thus, that of _Lepidodactylus
guppyi_, is founded on a single (female) specimen I found in Faro or
Fauro Island in Bougainville Straits. _Corucia zebrata_ never came under
my notice alive; it is said at Ugi to find its home in the foliage of
the higher trees. Doubtless if I could have penetrated to the higher
regions of the large islands, I should have obtained a large number of
new species. My collections refer for the most part to the sea-border
and its vicinity. In the elevated interior of such an island as
Guadalcanar there is _a region of great promise_ for the collector; but
I shall have a further occasion to refer to this topic.
The Monitor, _Varanus indicus_, may be often seen at the coast, basking
in the glare of the mid-day sun on the trunks of prostrate trees or on
the bare rocks. It is considered edible by the natives of Bougainville
Straits. Whilst we were anchored at Oima Atoll, Lieutenant Leeper
captured a very large specimen (5 feet 7¾ inches long)[442] on the rocks
close to the sea, and towed it off alive to the ship. After we had tried
in vain to strangle it by a cord, a lead was fastened to it and it was
sunk overboard, but an hour passed before we could say that the reptile
was really dead. This Monitor is probably able to swim considerable
distances. It very likely owes its wide range (from Celebes to the
Solomon Group including Cape York) to the agency of floating trees. On
examining the stomach and intestines, I found them empty. An enormous
quantity of fat, developed in two large lobes in connection with the
_omentum_ or some other part of the _peritoneum_, almost filled the
abdominal cavity. With this store of sustenance and heat, these reptiles
must be able to live without food for a long time.[443]
[442] A specimen shot in the Florida Islands measured 3 feet 8
inches.
[443] As an instance of the tenacity of life that some reptiles
possess, I may refer to the case of a young terrapin which I kept
inadvertently for nearly five months on the coast of China without
any sustenance except the dry rust of a tin can.
SNAKES. Hitherto, the following six species of Ophidians have been found
in the Solomon Group. All of them were included in my collection and one
of them has been described by Mr. Boulenger as a new species.
_Boidæ_
Enygrus carinatus
„ bibronii
_Colubridæ_
Dendrophis solomonis
Dipsas irregularis
_Elapidæ_
Hoplocephalus par _n. sp._
_Hydrophiidæ_ (_Water-snakes_)
Platurus fasciatus[444]
[444] I was indebted to Lieutenant Symonds of H.M.S. “Diamond” for
this snake.
One of the commonest of snakes throughout these islands is _Enygrus
carinatus_, a harmless species of the Boa family. It often possesses
considerable bulk in proportion to its length. One specimen which I
obtained in Treasury Island measured 3½ feet in length and 6 inches in
girth. I handled a good many living snakes whilst in these islands,
since the natives used to bring them in numbers to me both on board and
on shore. The statements of the natives and of the white men resident in
this region and the general appearance of the snakes had led me to
believe that there were no poisonous species in the group. I was
therefore somewhat surprised when, on my arrival in England, I learned
from Dr. Günther that I had found a new species as poisonous as the
Cobra. On being shown the specimen by Mr Boulenger, I at once recognised
an old friend which had been brought on board in a bamboo by the natives
at Faro Island and had got loose on the deck. Whilst the men standing
round were preparing to kill it with more regard for their own safety
than for my feelings, I caught it quickly around the neck and held it
under water until it was dead. The natives certainly were not aware of
its venomous character, nor was Mr. Isabell, who was my right-hand man
in these matters, and used to manage the ticklish progress of removing
the snakes from their bamboo-tubes in a manner only suitable in the case
of harmless species. I only obtained one specimen of this snake, which
was about 2½ feet in length. It is named _Hoplocephalus par_ and belongs
to the _Elapidæ_, a family of poisonous colubrine snakes which possess
the physiognomy of the harmless snakes of the same sub-order, and
include the Indian and African Cobras with other well known venomous
species. In the footnote I have quoted Mr. Boulenger’s description of
its general appearance for the information of those who visit the
group.[445]
[445] The upper surface of the head is uniform blackish brown. The
body is crossed above by broad red-brown bands separated by narrow
white interspaces. The lower surface of the head and body are
uniform white, except on the posterior extremity of the body where
the red and black extend as lines along the sutures of the ventral
shields. On the tail the red forms complete rings. Nearly every one
of the dorsal scales have a blackish brown border. The head is
depressed, moderately large, and slightly widened posteriorly. The
eye has a vertical pupil.
BATRACHIANS.--The Spanish discoverers in 1567 remarked that the natives
of Isabel worshipped the toad (_vide_ page 203), and one of the officers
of Surville’s expedition in 1769, described in his journal a remarkable
toad from the same island;[446] yet it is only within recent years that
any Batrachians have been collected in this region. Before I arrived in
the group only two species were known to science, and to this number my
collections, which were made in the islands of Bougainville Straits,
have added seven new species, including a type of a new family. The
following list represents the Batrachian fauna of the Solomon Islands,
as far as it is at present known:
[446] “Discoveries of the French in 1768 and 1769,” &c., by M.
Fleurieu: London, 1791; p. 134.
_Ranidæ._
Rana buboniformis, _n. sp._
Rana guppyi, _n. sp._
Rana opisthodon, _n. sp._
Rana krefftii.
Cornufer guppyi, _n. sp._
Cornufer solomonis, _n. sp._
_Ceratobatrachidæ._
(New family characterised by both jaws being toothed, and by the
diapophyses of the sacral vertebra not being dilated.) Ceratobatrachus
guentheri, _n. sp._
_Hylidæ_ (Tree-frogs.)
Hyla macrops, _n. sp._
Hyla thesaurensis.
The natives of the islands of Bougainville Straits, where, as I have
just remarked, my batrachian collection was chiefly made, have given
frogs the general name of “appa-appa” in imitation of their noise, just
as they have named the smaller lizards “Kurru-rupu” for the same reason.
Amongst the particular species of frogs, I may refer to the large
toad-like _Rana buboniformis_, which I found in Treasury Island, and on
the highest peak of the island of Faro. _Rana guppyi_, according to Mr.
Boulenger’s report, attains a larger size than any other species of the
genus, with the exception of the Bull-Frog of North America. _Rana
opisthodon_ affords an instance of a Batrachian[447] which dispenses
with the usual larval or tadpole stage, “the metamorphoses being hurried
through within the egg.” On this subject I made the following notes.
Whilst descending from one of the peaks of Faro Island, I stopped at a
stream some 400 feet above the sea, where my native boys collected from
the moist crevices of the rocks close to the water a number of
transparent gelatinous balls rather smaller than a marble.[448] Each of
these balls contained a young frog about 4 lines in length, apparently
fully developed, with very long hind legs and short fore legs, no tail,
and bearing on the sides of the body small tufts of what seemed to be
branchiæ. On my rupturing the ball or egg in which the little animal was
doubled up, the tiny frog took a marvellous leap into its existence and
disappeared before I could catch it. When I reached the ship an hour
after, I found that some of the eggs which had been carried in a tin had
been ruptured on the way by the jolting, and the liberated frogs were
leaping about with great activity. On placing some of them in an open
bottle 8 inches high, I had to put the cover on as they kept leaping
out. Mr. Boulenger remarking on this observation says, that there are no
gills, but that on each side of the abdomen there are regular transverse
folds (with an arrangement like that of the gill-openings of
Plagiostomous Fishes), the function of which probably is that of
breathing-organs. The tip of the snout is, he says, furnished with a
small conical protuberance, projecting slightly through the delicate
envelope of the egg, and evidently used to perforate that covering. In
the instance also of _Cornufer solomonis_, another new species included
in my collection, Mr. Boulenger remarks that there is every reason to
believe that the young undergo the metamorphoses within the egg.
[447] Hylodes martinicensis affords another instance. Mon. Berl.
Ac., 1876, p. 714.
[448] According to Mr. Boulenger, they measure from 6 to 10 mm. in
diameter.
With regard to the interesting species, _Ceratobatrachus guentheri_,
which forms the type of a new family, _Ceratobatrachidæ_, the same
writer observes that it is remarkable for the numerous appendages and
symmetrical folds which ornate its skin. It is, in fact, “all points and
angles,” and may be truly termed a horned frog. There is great variation
both in the coloration and in the integuments. “Out of the twenty
specimens before me,” thus Mr. Boulenger writes, “no two are perfectly
alike.” The development is presumed to be of the type in which the
metamorphoses are hurried through within the egg. These horned frogs are
very numerous in the islands of Bougainville Straits, and so closely do
they imitate their surroundings, both in colour and pattern, that on one
occasion I captured a specimen by accidentally placing my hand upon it
when clasping a tree.
It is particularly important to notice not only that the Batrachians of
the Solomon Islands, as far as we at present know, do not occur
elsewhere, but also that in this region a distinct family has been
produced. These facts support the conclusions deducible from the
geological evidence that these islands are of considerable geological
age (_vide_ page x.). The insular and isolated conditions have been
preserved during a period sufficiently extended for the development of a
peculiar Batrachian fauna.
The modes of dispersal of frogs and toads, and, in truth, of the whole
Batrachian class, are matters of which we are to a great extent
ignorant. Frogs are usually stated to be absent from oceanic islands, a
peculiarity of distribution which apparently accords with the
circumstance that neither they nor their spawn can sustain submersion in
sea-water. The occurrence, however, of three species of _Cornufer_ in
the Caroline and Fiji Islands, and of a species of _Bato_ in the
Sandwich Islands,[449] affects the general application of this
conclusion. It may be suggested that these exceptions are due to human
agency; but if so, it is difficult to understand why they have not been
found in such a well explored island as New Caledonia.[450]
[449] Boulenger’s “Catalogue of the Batrachia Gradientia,” &c., 2nd
edit., 1882.
[450] Perhaps the peculiar geographical distribution of the
Batrachia may throw light on this subject. _Ibid._
In concluding this chapter I will refer to the circumstance that my
collections of the Reptiles and Batrachians of this large group have
only in a manner broken ground in a region which promises the richest
results to the collector. It cannot be doubted that in the elevated
interiors of the large islands, such as those of Bougainville and
Guadalcanar, there will be found a peculiar Reptilian and Batrachian
fauna, the study of which will be of the highest importance for the
furtherance of our knowledge of these geologically ancient classes of
animals. I believe I am correct in stating that it was on account of the
highly interesting Batrachian collections I sent to the British Museum,
that I received a grant for further exploration from the Royal Society,
which, however, I was unfortunately prevented from turning to account.
The work has yet to be done, and there can be little doubt that the man
who is first able to examine the lofty interior of such an island as
Guadalcanar will bring back collections, the importance of which will
amply recompense him for any hardship or personal risk he may have
endured. My experience was confined to the sea-border and its vicinity.
The future explorer will find his field in the mountainous interiors and
on the highest peaks.
NOTE (April 19th, 1887).--Since I penned the above, further
collections of reptiles and batrachians, made in these islands by
Mr. C. M. Woodford, have been described by Mr. Boulenger at a recent
meeting of the Zoological Society. I had the pleasure of meeting Mr.
Woodford before he left England, and I hope that he has been able to
accomplish his purpose of penetrating into the interior of one of
the larger islands of the group.
CHAPTER XV.
GENERAL NATURAL HISTORY NOTES.
AMONGST the numerous strange acquaintances which I made in the Solomon
Islands, was that of the well known cocoa-nut crab, or _Birgus latro_;
and I take this opportunity of giving my evidence towards the
establishment of the fact of its cocoa-nut-eating propensity, for the
following reason. When I read my notes on the subject before the Linnean
Society of New South Wales on Dec. 27th, 1882,[451] I was surprised at
the incredulity shown with reference to this extraordinary habit; and on
inquiry, I learned that the evidence on the subject was deficient in one
vital point, viz., the production of the writer who had witnessed this
habit of the Robber Crab. Accordingly I referred to the various authors
who have recorded this habit of the _Birgus_, and in no single account
could I find that the writer had witnessed what he described. Neither
Mr. Darwin, Dr. Seemann, Messrs. Tyerman and Bennet, Mr. T. H. Hood, the
Rev. Wyatt Gill, nor the numerous authors whose accounts I also
examined, seem to have actually witnessed the _Birgus_ opening and
eating a cocoa-nut. Herbst[452] was among the first to refer to this
habit; whilst, long ago, M. M. Quoy and Gaimard[453] asserted, from
their own observation, that the crab was fond of cocoa-nuts, and could
be supported on them alone for many months, but they made no allusion to
its capability of husking and opening them. The evidence on this point
appears to have been always tendered by natives, excepting the account
given to Mr. Darwin by Mr. Liesk, which is conclusive in itself.[454]
Yet, credulous persons had fair grounds to retain their doubts, although
in various works on natural history, popular and otherwise, this habit
of the _Birgus_ was described as an undoubted fact. I therefore submit
my evidence; leaving to my reader to reply to the query--Can there be
any reasonable doubt on the subject?
[451] Proc. Lin. Soc. N.S.W.
[452] Proc. Zool. Soc, 1832, p. 17.
[453] Freycinet’s “Voyage autour du Monde,” 1817-20: Zoologie, p.
536. (Paris, 1824.)
[454] “Journal of Researches,” p. 462.
The _Birgus_ was to be found in most of the islands we visited. It is to
be usually observed at or near the coast; but on one occasion, in St.
Christoval, I found an individual at a height of 300 feet above the sea.
Whilst traversing, in September, 1882, the belt of screw-pines, which
borders the beach on the east coast of Malaupaina, the southern island
of the Three Sisters, I came upon one of these large crabs, ensconced in
the angle between the buttressed roots of a tree, with a full sized
cocoa-nut within the reach of its pair of big claws. From the
fresh-looking appearance of the shell, it had been evidently, but
recently, husked, which operation had been performed more cleanly than
if a native had done it. There was an opening at the eye-hole end of the
shell of a somewhat regular oblong form, which measured 2 by 1½ inches,
and was large enough to admit the powerful claws of the crab.[455] The
white kernel, which had the firm consistence of that of the mature nut,
had been scooped out to the extent of from 1 to 1½ inches around the
aperture; small pieces of the kernel lay on the ground outside the nut,
and others were floating about in the milk inside, of which the shell
was about a fourth-part full.
[455] This shell was presented to the Australian Museum, Sydney.
I had, without a doubt, disturbed the _Birgus_ in the middle of its
meal; but, curiously enough, there were no cocoa-nut palms to be seen
within fifty paces of the spot where the crab was found in its retreat.
Not only had the shell been very recently husked, but it was evident,
from the fresh condition of the milk and kernel, that an interval of
less than a couple of hours had elapsed since the opening had been made.
There was no possible explanation of the crab having got at the edible
portion of the cocoa-nut, except through its own agency. The island is
uninhabited, being only occasionally visited by fishing-parties of
natives from St. Christoval, none of whom were on the island during the
ship’s stay. There was, therefore, the strongest presumptive evidence
that the _Birgus_ had not only husked the cocoa-nut, but had also broken
the hole at the end, in order to get at the kernel.
I kept the crab alive on board on a diet of cocoa-nuts for three weeks,
when, one morning, to my great disappointment, I found it dead. Other
foods, such as bananas, were offered to it but were left untouched, and
its appetite for cocoa-nuts continued unimpaired to the last day of its
life. Being desirous of observing the manner in which the husk was
removed, I had a cocoa-nut with its husk placed in the coop in which the
crab was kept. On one occasion the _Birgus_ was surprised with the nut
between its large claws; but, notwithstanding that no other food was
offered to it for a day and a half, it did not attempt to strip off the
husk. So the operation was done for it, and a small hole was knocked in
the top of the shell. On the following day I found the shell--a young
and somewhat thin one--broken irregularly across the middle, with the
soft white kernel already removed and eaten. It was afterwards found
necessary to break the nuts for its daily food.
In 1884, when the “Lark” was in Bougainville Straits, three of these
crabs were kept on board with the intention of taking them down to
Sydney. Mr. W. Isabell, leading-stoker of the ship, looked well after
them, as he had also done in the case of the previous crab, but within
three or four weeks they had all died. The cocoa-nuts had to be husked
and broken for them, as they were in vain tempted to do it for
themselves. One crab, however, was frequently observed clasping between
its claws a full-grown unhusked nut, the upper end of which showed deep
grooves and dents from the blows of its claws; and Mr. Isabell and I
came to the conclusion that the coop, in which these crabs were placed,
was too low to allow of the free play of the great claws.
My evidence alone would be sufficient to convict the _Birgus_ of this
offence: for an offender it would certainly be in the eyes of the owner
of a plantation of cocoa-nut palms. I learned from Mr. Isabell that the
first crab we had on board consumed, on the average, two cocoa-nuts in
three days. A number of these crabs in a cocoa-nut plantation, might
therefore prove a considerable pest: for, if this betokens the quantity
of food which the _Birgus_ consumes in a state of nature, a single crab
in the course of twelve months would dispose of about 250 cocoa-nuts,
which represent the annual production of three palms and between 20 and
30 quarts of oil.
As these crabs disliked observation, I was unable to gain much knowledge
of their habits by watching. During the day-time they were sluggish, did
not eat, and kept themselves in the further corner of the coop, as far
from the light as possible. At night they moved about very actively and
fed vigorously on the cocoa-nuts. The natives of the Shortlands, who
were well-acquainted with the cocoa-nut eating habit of the _Birgus_,
described to me the mode of husking and breaking the nut, just as Mr.
Liesk described it to Mr. Darwin. They esteem as an especial luxury the
fat which gives the chief bulk to the abdomen of the crab.
The habit of the _Birgus_, when surprised away from its burrow, is not
to turn round and run away, but to retreat in an orderly manner with its
front to the foe. Having reached some root or trunk of a tree which
protects in the rear its less perfectly armoured abdomen, it makes a
regular stand, waves one of the long second pair of claws in the air,
and courageously awaits the attack. The attitude of defence is worthy of
remark. The two large claws are held up close together to defend the
mouth and eyes, but with the pincers pointing downward--the posture
reminding me of the guard for the head and face in sword-exercise. One
of the long second pair of claws is planted firmly on the ground to give
the crab additional support; whilst the other claw is raised in the air
and moved up and down in a sparring fashion. The whole attitude of the
_Birgus_, when on the defensive, is one of dogged and determined
resistance. The big pincers that point downward are ready to seize
anything which touches the unprotected under surface of the abdomen; but
on account of the position of these claws in front of the eyes, it can
only foresee attacks from above, and it therefore cannot ward off a
sudden thrust directed against the abdomen, although it may afterwards
inflict severe injuries on the aggressor.
There seems to be some doubt whether the _Birgus_ ascends the tree to
get the cocoa-nuts or whether it contents itself with those that have
fallen. Almost every author who refers to this crab alludes to its
climbing the tree, and it is also said to climb the pandanus. The
testimony in support of its climbing powers is almost conclusive, yet
Mr. Darwin was informed by Mr. Liesk that in Keeling Atoll the _Birgus_
lives only on the fallen cocoa-nuts, and Mr. H. O. Forbes,[456] who has
recently visited this island, confirms this statement.
[456] “A Naturalist’s Wanderings,” etc.: London, 1885, p. 27.
My readers, after perusing the foregoing remarks, will agree with me
that from the lack of actual observation on the part of the authors, who
describe the cocoa-nut eating habit of this crab, there has been fair
grounds for scepticism. Even now, we are but imperfectly acquainted with
the mode of life of the _Birgus_, which is a subject I would commend to
the attention of residents in the Indian and Pacific Oceans.
I may add that the _Birgus_ is partial to other kinds of fruits beside
cocoa-nuts. Different writers mention candle-nuts, nutmegs, figs, and
other rich and oily nuts and fruits. In some islands it would seem that
the Pandanus fruit is its only diet; and for breaking open these tough
fruits, its heavy claws are well adapted, though from personal
experience, I should remark that the crab would have its strength and
ingenuity taxed almost as much as in the case of the cocoa-nut.
[Illustration]
The handsome ground-pigeon, known as the Nicobar pigeon (_Geophilus
nicobaricus_), is commonly observed in the wooded islets on the coral
reefs of the Solomon Group. As I have remarked on page 293, this bird is
probably instrumental in transporting from one locality to another the
small hard seeds and fruits which the common fruit-pigeon (_Carpophaga_)
refuses. That it is able to crack such hard seeds as those of the
leguminous plant _Adenanthera pavonina_,[457] is shown by the fact that
I have found these seeds cracked in the cavity of the gizzard, which is
in its structure and mechanism _a veritable pair of nutcrackers_. In
this bird the muscular stomach or gizzard is of a surprising thickness,
and is provided with a very singular mechanical contrivance to assist
its crushing power. As shown in the accompanying diagram, it is composed
of two muscular halves, each having a maximum thickness of five-eighths
of an inch and united with each other in front and behind by a stout
distensible membrane, which is the proper wall of the organ. Developed
in the horny epithelial lining membrane there are two cartilaginous
bodies of hemispherical shape, one in each muscular segment of the
gizzard, which measure about one-third of an inch in thickness and
three-fourths of an inch in diameter. The outer or convex surface of
each cartilaginous body fits into a cup-shaped cavity which is lined by
a semi-cartilaginous membrane, the whole constituting a
“ball-and-socket” joint with well lubricated surfaces. The two surfaces
of this pseudo-articulation are capable of easy movement on each other,
being retained in close apposition by the attachment to the subjacent
tissues of the horny epithelial lining membrane in which the
cartilaginous body is developed. The inner or free surface of each
hemispherical body, that which looks into the gizzard cavity, is
somewhat concave, and projects a little above the surface of the lining
membrane; it is much harder than the opposite convex side of the
cartilage and has almost the consistence of bone, the arrangement of the
cells into densely packed rows with but little intervening matrix
indicating an approach towards ossification.
[457] The Kuara tree of India, of whose hard seeds necklaces are
made.
The firm consistence of these hemispherical cartilages combined with the
mechanism of a moveable articulation must greatly assist the already
powerful muscular walls of the gizzard; but there is an additional
factor in the crushing power in the constant presence of a small quartz
pebble, usually about half-an-inch across. With such a apparatus, I can
well conceive that very hard seeds and nuts may be broken, as in the
case of the seeds of _Adenanthera pavonina_ already alluded to. The
Nicobar pigeon is in fact possessed of a nut-cracking mechanism in its
gizzard, by which nuts like those of our hazel tree would be cracked
with comparative ease.
With reference to the small quartz pebbles found in the gizzards of
these birds, I should remark that there is usually only one present, and
that it varies in weight between 30 and 60 grains. I was sometimes able
to say where the pigeon had obtained its pebble. Thus, in Faro Island
the bird often selects one of the bipyramidal quartz crystals, which
occur in quantities in the beds of the streams in the northern part of
the island, where they have been washed out of the quartz-porphyry of
the district. In other instances the pebble seems to have been
originally a small fragment of chalcedonic quartz, such as composes some
of the flakes and worked flints that are found in the soil which has
been disturbed for cultivation. Sometimes the pebble is of greasy
quartz; and now and then in the absence of quartz the bird has chosen a
pebble of some hard volcanic rock. It is a singular circumstance that
although these pigeons frequent coral islets where they can easily find
hard pebbles of coral-rock, they prefer the quartz pebbles which are of
comparatively rare occurrence. I never found any calcareous pebble in
their gizzards, and was often at a loss to explain how the bird was able
to ascertain for itself the different degree of hardness between the two
pebbles, when the quartz was of the dull white variety. . . . . I learn
from a recent work on New Guinea by the missionaries, Messrs. Chalmers
and Gill, that inside the gizzard of each Goura pigeon there is a
good-sized pebble much prized by the natives as a charm against
spear-thrusts and club blows.[458] The Goura pigeon resembles the
Nicobar pigeon in habits; and I think it probable that its gizzard will
be found to present a similar structure and mechanism for cracking nuts
and hard seeds. The common fruit pigeons (_Carpophaga_) of the Solomon
Islands, living as they do on soft fleshy fruits, and rejecting the hard
seeds and kernels, have no peculiar structure of the gizzard, the walls
of which are comparatively thin, and are thrown into permanent rugæ
somewhat warty oh the surface.
[458] “Work and Adventure in New Guinea” (p. 317): London, 1885.
One of the most familiar birds in these islands is the “bush-hen,” which
belongs to the family of the mound-builders (_Megapodiidæ_). They bury
their eggs in the sand at a depth of between three and four feet. On one
occasion in the island of Faro, Lieutenant Heming and his party found
eight eggs, in different stages of hatching, thus buried: they were
scattered about in the sand; and according to the account of the natives
only one egg was laid by each bird. The eggs are sometimes found on the
surface of the sand. The young birds are able to fly short distances
soon after they are hatched. One that was brought on board astonished us
all by flying some thirty or forty yards from the ship and then
returning to the rigging.
The account recently published by Mr. H. Pryer of his visit to the
birds’ nest caves of Borneo[459] has opened up the discussion as to the
nature of the substance of which the edible bird’s nest is composed.
Many and varied have been the surmises as to the source of this
material; but nearly all of them have been based on mere speculation,
and have been relegated to the limbo of sea-tales. Amongst the earlier
explanations, I may allude to those which have been given by early
writers. The swiftlets (_Collocalia_), which build their nests in this
extraordinary fashion, were considered to gather a gelatinous material
from the ocean-foam, or from the bodies of holothurians, or from the
skin of the sun-fish. The Chinese fishermen assured Kæmpfer that their
nests were composed of the flesh of the great poulpe. A more probable
explanation, however, was found by Rumphius in the occurrence on the
sea-coasts of a soft almost cartilaginous plant which he with confidence
asserted was the material from which these swiftlets constructed their
nests; but subsequently this naturalist inclined to the opinion that the
substance of which the edible birds’ nests are composed is merely a
secretionary product. In these two views of Rumphius we have the two
sides of the controversy very much as it at present stands. On the one
hand, there are those who hold that this substance is a secretionary
product: on the other hand, the opinion is held that the nest is
constructed of a vegetable matter, usually resulting from the growth of
a microscopic alga, which is found in the caves and on the faces of the
cliffs where the nests occur. All the weight of experiment and of actual
observation tends to negative the view of the vegetable origin of this
substance. Sir Everard Home in 1817 declared his opinion that certain
peculiar gastric glands, which he found in one of these birds, secreted
the mucus of which the nest was formed. In 1859, Dr. Bernstein[460],
after having carefully studied the habits of the birds in question, came
to the conclusion that their nests are formed from the secretion of
certain salivary glands which are abnormally developed during the
nest-building season. M. Trécul, who held the same opinion, showed that
the bird constructs its nest by means of a mucus which flows abundantly
from its beak at the pairing time.[461] This last view is strongly
supported by Mr. Layard, who unhesitatingly pronounces his opinion that
these swiftlets build their nests from the secretionary products of
their own salivary glands.[462] However, when Mr. Pryer visited in
March, 1884, the birds’ nest caves in British North Borneo, he
considered that he had found the source of the material of which the
nests were composed in the occurrence of a “fungoid growth,” which
incrusted the rock in damp places, and which, when fresh, resembled
half-melted gum tragacanth. Without at present expressing an opinion as
to the validity of the inference Mr. Pryer drew from his observations in
these caves, I may observe that the “fungoid growth” has been determined
by Mr. George Murray,[463] of the Botanical Department of the British
Museum, to be the result of the growth of a microscopic alga, a
species, probably new, of _Glœocapsa_; whilst the edible nests from
these caves, according to a chemical and microscopical examination made
by Mr. J. R. Green,[464] have been shown to be formed in the great mass
of _mucin_, which is the chief constituent of the mucous secretions of
animals. After examining various specimens of edible nests from other
localities, Mr. Green subsequently confirmed the results of his first
experiments. The nest-substance, as he unhesitatingly states, is
composed of _mucin_, or of a body closely related to it.[465] So far,
therefore, there would appear to be but little evidence to support the
view of Mr. Pryer that the species of alga, which he found incrusting
the rock in the vicinity of the Borneo caves, supplied the material for
the construction of the nests of the swiftlets. However, before
proceeding to state my own opinion on the matter, I will refer briefly
to my observations in the Solomon Islands relating to this question.
[459] Proceedings of the Zoological Society for 1884: p. 532.
[460] Journ. für Ornithologie, 1859, pp. 112-115; also Proceed.
Zoolog. Soc., 1885, p. 610.
[461] “A General System of Botany,” by Le Maout and Decaisne:
London, 1873, p. 983.
[462] “Nature,” Nov. 27th, 1884.
[463] Proc. Zoolog. Soc., 1884: p. 532.
[464] Proc. Zool. Soc., 1884, p. 532.
[465] “Nature,” Dec. 11th, 1884 and May 27th, 1886.
A species of _Collocalia_, which usually frequents inaccessible
sea-caves and cliffs, is frequently to be observed on the coasts of the
islands of this group. The natives of Treasury Island call this bird
“kin-kin;” but they have no knowledge of the nutrient qualities of the
substance of which it builds its nest, and they were much amused when I
told them of its being a Chinese luxury. I only came upon the nests of
this bird on one occasion, and that was in some caves on Oima Atoll in
Bougainville Straits. A description of these caves will be here
unnecessary. As in the instance of the birds of the Borneo caverns,
these swiftlets shared their retreats with a number of large bats, the
accumulation of whose droppings had produced a thick reddish-brown
deposit on the floors of the caves. The nests, which were formed for the
most part of fibres derived evidently from the vegetable drift[466] at
the mouths of the caves, were thickly incrusted with the gelatinous
incrustation which projected as winglets from the sides and fastened
them to the rock.
[466] The husks of pandanus seeds more particularly.
A reddish soft gelatinous incrustation occurred on the faces of some of
the cliffs in the vicinity of the caves. It was composed of an
aggregation of the cells of a microscopic unicellular alga which measure
1/2500 of an inch in diameter. Unfortunately the specimens of this
growth which I collected have been mislaid, but there can be little
doubt that it is similar to the “fungoid growth” which Mr. Pryer
describes in connection with the Borneo caves, and which, through the
kindness of Mr. George Murray, I had the opportunity of seeing at the
British Museum. On the faces of the coral limestone cliffs of some
islands, such as on the east coast of Santa Anna, a like growth occurs
in considerable quantity. In its freshest condition, it may be described
as a reddish-yellow, gum-like substance forming a layer ¼ to ⅛ of an
inch in thickness. Where it incrusts the overhanging face of a cliff, it
is more fluid in consistence and sometimes hangs in little pendulous
masses, one to two inches in length, the extremities of which are often
distended with water. This alga decomposes the hard coral limestone,
making the surface of the rock soft and powdery. All stages in the
growth of this substance may be observed. The older portions are very
dark in colour and have a tough consistence; and in the final stage it
occurs as a black powder covering the rock surface. On examining this
alga with the microscope, I found it to be formed almost entirely of
granular matter apparently resulting from the death of the cells; whilst
the presence of a few cellular bodies alone gave me an indication of its
true nature.
From my observations relating to the subject of the edible bird’s nest,
it may be therefore inferred that in the Solomon Islands, as in Borneo,
the occurrence of these nests is associated with the presence of a
protophytic alga, which incrusts the rocks of the locality as a
gelatinous or gum-like substance. Whether or not the birds employ this
material in forming their nests, is a question which would appear to
have been already answered in the negative; but it seems to me that
those who hold that this material is used for this purpose might justly
claim that the final judgment should be suspended, until a chemical
examination of this vegetable substance has been made with the object of
determining whether it might not yield a material closely resembling
_mucin_. Amongst the nitrogenous constituents of plants occurs the
so-called _vegetable albumen_, which in its chemical composition and in
its behaviour with re-agents does not differ materially from the
_blood-albumen_ of the animal organism, of which in fact it is the
source. In suggesting, therefore, that a _vegetable mucin_ may be found
in this low plant-growth, I do not pass beyond the bounds of
probability.[467]
[467] _Vide_ a letter by the writer in “Nature,” June 3rd, 1886.
Small scorpions came under my notice in Faro Island. They are not
usually more than 1½ in length and occur in narrow clefts of rocks and
in the crevices of trees. I was stung by one on the thumb, but the pain
was trifling and soon passed away.[468]
[468] Specimens of these scorpions were given by me to the
Australian Museum, Sydney.
A species of _Iulus_ or Millipede, which attains a length of from 6 to 7
inches, is commonly found in the eastern islands of the Solomon Group on
the trunks of fallen trees and amongst decaying vegetable débris. It is
often to be seen amongst the rotting leaves that have gathered inside
the bases of the fronds of the Bird’s-nest Fern (_Asplenium nidus_).
These Myriapods seem to be less frequent in the islands of Bougainville
Straits towards the opposite end of the group, as I do not remember
seeing any large _Iuli_ in that locality: their place appears to be
taken by another Myriapod, apparently a _Polydesmus_, growing to a
length of 2½ inches, which I found amongst decaying vegetation at all
elevations up to 1900 feet above the sea, as on the summit of Faro
Island. But to return to the _Iuli_, I should remark that this genus of
Myriapods evidently possesses some means of transportal across wide
tracts of sea, since, amongst other islands similarly situated, it is
found in Tristan da Cunha,[469] in the South Atlantic Ocean, and I have
found it in the Seychelles, in the Indian Ocean. The habits of these
Millipedes would render it highly probable that they have reached the
oceanic islands on vegetable drift, such as floating logs. It is,
however, a noteworthy circumstance that they do not seem to be able to
withstand immersion in sea-water for any length of time. In
experimenting on the Solomon Island species, I found that they were able
to survive an hour-and-a-half’s complete immersion in sea-water, but
that an immersion of three hours killed them. One individual, out of
several experimented on, survived for twelve hours after it was taken
out, but only in a half lifeless condition.[470] It may, therefore, have
been that the _Iulus_ has been transported to oceanic islands by such
agencies as canoes and ships, rather than by means of floating
trees.[471]
[469] Moseley’s “Naturalist on the Challenger,” p. 134.
[470] This species of _Iulus_ was able to sustain a longer
submersion in fresh-water, without apparently any injurious effects.
Those experimented on recovered after being kept under water for
four hours, but died after a submersion of six hours.
[471] As bearing on this point, it might be interesting to determine
whether these large _Iuli_ occur on islands far from land which are
believed never to have been inhabited.
Like other species of the genus, the Solomon Island _Iulus_ exhales a
very pungent and disagreeable odour, which is caused by an acrid fluid
secreted by small vesicles, of which each segment of the body contains
a pair.[472] On holding my nose for a moment over the mouth of a bottle,
containing two of these large Millipedes, I experienced a strong
sensation in the nasal passages, reminding me much of the effects of an
inhalation of chlorine gas. I had previously learned from resident
traders that these Millipedes have a habit of ejecting an acrid fluid
when disturbed, which, if it entered the eye, was liable to cause acute
inflammation; and the instance was related to me of the captain of some
ship, trading in these islands, who lost the sight of one of his eyes
from this cause. Mr. C. F. Wood learned from the natives of St.
Christoval, in 1873, that these Myriapods “could squirt out a poisonous
juice, which was dangerous if it happened to touch one’s eye;” but he
adds, “there seemed no great probability of their doing this.”[473]
However, I usually found that native testimony, in such matters, was
very reliable; and in the instance of this reputed habit of the _Iulus_,
my personal experience has convinced me of its reality. Whilst handling
one of these Millipedes as it lay on the trunk of a fallen tree in Ugi
Island, I felt a sudden smarting sensation in the right eye, caused
apparently by some fluid ejected into it. Remembering the injurious
effect attributed to this habit of the _Iulus_, I at once plunged my
head under the water of a stream, in which I happened to be standing up
to my waist, and I kept my eye open to wash away the offending fluid.
During the remainder of the day, there was an uncomfortable feeling in
the eye and somewhat increased lachrymation; but on the following
morning these effects had disappeared. At the time of this occurrence,
my face was removed about a foot from the Millipede; and, although I was
uncertain from what part of the body the fluid was ejected, I did not
care, under the circumstances, to continue the inquiry.
[472] Hoeven’s Zoology. (Eng. edit.) Vol. I., p. 291.
[473] “A Yachting Cruise in the South Seas,” p. 131. (London, 1875.)
* * * * *
Amongst the first living creatures to greet the visitor as he lands on
the beach of a coral island in the Pacific, is a small species of
Hermit-Crab, belonging to the genus _Coenobita_, which frequents the
beach in great numbers. The crab withdraws itself just within the mouth
of the shell, where it forms a perfect operculum, by means mainly of the
large flattened _chelæ_ of the left great claw which is arched over by
the left leg of the third pair, whilst the right claw and the right leg
of the second pair serve to complete the shield The most plucky and
pugnacious of these little crabs are those which occupy cast-off
_Nerita_ shells, a character which probably arises from their
consciousness of the solid strength of the home they have chosen: and,
strange to say, the tiny bosses on the surfaces of the large pincers,
which are outermost in the improvised operculum, resemble similar
markings on the outer side of the operculum of the _Nerita_ (_N.
marmorata_, Hombr and Jacq), whose shell they often inhabit. Mr.
Darwin[474] observed that the different species of hermit-crabs, which
he found on the Keeling Islands in the Indian Ocean, used always certain
kind of shells; but I could not satisfy myself that such was the case in
the instance of the Solomon Island hermit-crabs. In the case of the
common beach species of _Coenobita_, I found, after carefully examining
a number of individuals to satisfy myself of their being of the same
species, that shells of the genera _Turbo_, _Nerita_, _Strombus_,
_Natica_, _Distorsio_, Truncatella, _Terebra_, _Melania_, &c., &c.,
contained the same species of _Coenobita_, whether the individual was
large enough to occupy a _Turbo_ shell of the size of a walnut or
sufficiently small to select the tiny shell of the _Truncatella_ for its
home. Another species of the same genus prefers usually the vicinity of
the beach; but it may occur at heights up to 200 feet above the sea. It
is rather larger than the beach species, and differs amongst other
characters in the more globose form of the large claws and in the
greater relative size of the left one. It occupies shells of different
kinds, such as those of _Nerita_, _Turbo_, &c. A still larger species,
which frequents the vicinity of the beach, usually selects _Turbo_
shells, apparently because of their larger size. All the other species
of _Coenobita_, which I met with, used, when I touched them, to withdraw
themselves within their shells and close them up at once with their
claws; but this kind, when I caught hold of the _Turbo_ shell that it
carried, left the shell behind in my fingers with apparent unconcern and
crawled leisurely away, displaying, somewhat indecorously, the
rudimentary plates on the back of its abdomen. These are the plates that
attain their greatest development in the Cocoa-nut Crab (_Birgus
latro_), which is thus able to dispense with a shell altogether. The
greatest heights at which I found hermit-crabs were in the island of
Faro on the two highest peaks, which are elevated respectively 1600 and
1900 feet above the sea. In both these localities, the crab had reached
the very summit and could not have climbed higher. The species was
apparently different from, though closely allied to, the common beach
species, and frequented the shells of a land-snail (_Helix_). I was
indebted to Lieutenant Heming for directing my attention to the
hermit-crab, found 1900 feet above the sea. It appears to me likely that
these hermit-crabs will be found at much greater heights in this group,
since, in this island, their ambition to rise had carried them up as far
as they could go.
[474] “Journal of the Beagle,” p. 457.
Other species of hermit-crabs, that are common in these islands, belong
to the genus _Pagurus_. They are conspicuously distinguished from the
species of _Coenobita_, above described, by their first pair of claws,
which are small and weak and ill-adapted for defensive purposes. For
this reason, these species are less able to look after themselves; and
since they cannot form the operculum-like shield with their claws at the
mouth of the shell, they always choose shells which will permit of their
retiring well within it, so as to be out of the reach of their enemies.
Some species are found in the stream-courses and in the brackish water
near their mouths, when they often frequent cast-off _Melania_ shells.
Other species (?) prefer the sea-water on the reef-flats. I noticed one
individual that displayed its eccentricity of disposition, in selecting,
as its abode, the hollow tube of a small water-logged stick, about six
inches long, which it dragged about after it during its peregrinations,
and into which it retreated when alarmed. On one occasion, I observed a
large _Dolium_ shell, moving briskly about in a pool of salt-water,
which, on picking up, I found to be tenanted by a _Pagurus_, so
ridiculously small, in comparison with the size of the shell, that when
frightened it retreated to the very uppermost whorl, and,
notwithstanding the wide mouth of the shell, could not be seen. So light
was the weight of the crab, that, on account of the buoyancy of its
shell, it floated lightly on the surface of the water, on which I had
placed it with the mouth of the shell uppermost, and was blown by a
slight breeze across a pool of water, some twenty yards in width. While
it was afloat, the shrewd little occupant retired to the innermost
recess of its home; but as soon as the shell had grounded, it protruded
its head and pincers and endeavoured to overturn the shell, which it
finally succeeded in accomplishing.
In the case of these two genera of hermit-crabs, _Coenobita_ and
_Pagurus_, it was interesting to notice the relation existing between
the defensive capabilities of the crab, and the relative size of the
shell it selected as its home. The _Pagurus_, with its weak slender
pincers, chooses large shells within which it can retire well out of
reach when alarmed. The _Coenobita_, with its stout pincers, prefers
shells much smaller, relatively speaking, and ensconces itself snugly in
the body whorl, forming an operculum with its claws. As the hermit-crab,
_Coenobita_, crawls along the dry sand of a beach, it leaves behind it
characteristic pinnate tracks which may be often traced for several
feet. The lateral markings are produced by the claws and legs working on
each side of the shell; whilst a central groove is formed by the weight
of the shell itself. As shown by the arrow in the diagram, the lateral
markings point in the direction of the course which the hermit-crab has
taken. Sometimes only a single row of lateral tracks accompanies the
grooves produced by the shell. Such markings were produced by a
hermit-crab when frightened by my approach. It turned its front towards
me, and crawled backwards, by working most of his claws and legs on one
side of the shell. In the case of the larger hermit-crabs, which are
much less frequent on the beach, each limb produces a distinct print on
the sand; but with the small species of _Coenobita_ which infests the
beach, each lateral marking, as shown in the diagram, is produced by a
single movement of the claws situated on the same side of the shell. The
hermit-crabs only leave their tracks on the dry loose sand. One
individual, that I placed on sand, still wet from the retreating tide,
crawled along without leaving any impression. I have described these
impressions with some care, as they bear on the origin of the
surface-markings of rocks of shallow-water formation, a subject recently
discussed in the geological world. It is highly probable that some of
the larger and heavier forms of the Anomura (and, in fact, of the
Decapoda generally) would produce prints such as I have here described,
both on mud-flats left dry by the tide, and on the soft bottom in
shallow depths. A cast of the impressions thus produced would have an
unmistakeable plant-like form.
[Illustration]
Whilst examining the island of Simbo, I noticed some singular Medusæ in
a small mangrove-swamp, which is inclosed in the low point that forms
the south shore of the anchorage. Numbers of these organisms of a large
size (8 or 9 inches across the umbrella), and of a dirty-white colour,
were lying on the mud with their tentacles, uppermost in depths of from
one to three feet of water. I was struck by the handsome mass of
arborescent tentacles which they displayed, and by the peculiarity of
their lying upside-down. The dark mud which formed the bottom of the
swamp was composed of decayed vegetable matter, confervoid growths,
diatoms, and a few infusoria: but when I raised up these Medusæ, I found
underneath each a patch of white sand corresponding with the outline of
the organism, but completely concealed by the umbrella when the Medusa
lay in its usual position. The sand was derived from corals, shells, and
the volcanic rocks of the island; and the light patches formed a marked
contrast with the dark mud around. I was unable to find any satisfactory
explanation of these curious patches of sand; and I, therefore,
proceeded to interrogate the Medusæ on the subject by watching them, but
to no purpose. So I had my revenge by turning them all over on their
tentacles, when each one immediately began to contract its umbrella in a
most methodical fashion, and, after swimming a short distance,
deliberately resumed its former position of tentacles upward. I had an
extensive experience of mangrove-swamps after we left Simbo; but these
self-willed Medusæ never came under my notice again.[475]
[475] I referred to the habits of these Medusæ in “Nature,” Nov.
9th, 1882.
With regard to these Medusæ, I should remark that they belong to a
species of _Polyclonia_, and are classed amongst the Scypho-Medusæ.[476]
Two species of _Polyclonia_ seem to be known, _P. frondosa_ (Agassiz)
and _P. Mertensii_(Brandt), the first found in the Florida seas, and the
latter in the Carolines. I am inclined to think that the Solomon Island
species is more nearly allied to _P. Mertensii_. Both species, however,
have similar habits, lying on the mud of mangrove-swamps, with their
tentacles uppermost.
[476] I compared my notes with the description and figures given by
Agassiz in his “Contrib. Nat. Hist. U.S.A.” (1862: vols. iii. and
iv.). In the Solomon Island species, the dendriform mass resolves
itself into 8 principal branches, each ramose, and all united at
their bases by a common membrane. The umbrella, which was finely
lobed or crenulated at its margin, displayed about 40 radiating
canals, each communicating by an anastomosing network with the canal
on either side of it.
The singular habits of these Scypho-Medusæ were noticed by Brandt in
1838. They have since been remarked by Mosely[477] in the Philippines,
and by Archer[478] in the West Indies. L. Agassiz in his “Contributions
to the Natural History of the United States,” describes and figures the
Florida species (_Polyclonia frondosa_); and some additional notes on
its habits have been made by A. Agassiz, to whose communication in
“Nature” (Sept. 29th, 1881) I have been much indebted.
[477] Mosely’s “Notes by a Naturalist,” p. 404.
[478] “Nature” Aug. 4th, 1881.
Whilst we lay at anchor in Treasury Harbour, in April, 1884, a cetacean,
unknown to the natives and to ourselves, got partly stranded in the
shallow water, and was captured by the villagers. It was nine feet long,
and possessed this remarkable character that, although no teeth showed
through the gums, each lower jaw possessed a short, conical, hollow
tooth an inch long, placed at the anterior extremity. I obtained the
head from the natives, and placed it in a safe place, as I thought; but
when we returned to Treasury a few weeks after, I found only portions of
the skull with the lower jaw-bones, the wild pigs having held a feast
over it. The remains, however, together with my notes and a sketch by
Lieutenant Leeper were sent to the British Museum. I there learned that
it is a species of Ziphius, probably unknown.
The Solomon Islanders believe in the existence of anthropoid apes in the
interiors of the large islands, regarding them, however, like the Dyaks
of Borneo in the case of the Orang-utan, as “wild men of the woods.” In
Malaita they are said to be 4½ to 5 feet high, and to come down in
troops to make raids on the banana plantations. Captain Macdonald
informed me that the natives allege that one of these apes was caught,
and, after being kept for some time, escaped. Taki, the St. Christoval
chief, told Mr. Stephens that he had seen one of these apes, and pointed
out the locality. Tanowaio, the Ugi chief, also made a similar
statement. In Guadalcanar, they are believed to live in the trees, and
to attack men. Dr. Codrington refers to the prevalence of these beliefs
throughout Melanesia (Journ. Anthrop. Inst., vol. x. p. 261). Such
beliefs, as experience has shown in the case of the Gorilla and other
anthropoids, have undoubtedly some foundation; but whether these
mysterious animals are apes is quite another question.
CHAPTER XVI.
LAND AND FRESH-WATER SHELLS.
DURING my numerous excursions in these islands, I had in the majority of
instances to follow up the stream-courses in order to examine their
geological structure. I had therefore good opportunities in these
regions of making a collection of the fresh-water shells, which,
together with the land shells I collected, formed a total of between
sixty and seventy species, amongst which there were 11 new species and
at least 5 new varieties, whilst about 14 would appear to have been
never previously recorded from the Solomon Islands, and there were in
addition several from new localities in the group. The collection was
sent to the British Museum and was examined and described by Mr. E.
Smith, to whose paper on the subject[479] I am indebted for my
acquaintance with the shells in question, and through whose kindness I
have been thus enabled to supplement my other observations in these
islands. A list of the shells with the descriptions of the new species
is given on page 344. For its size, my collection presented a large
amount of novelty, coming as it did from a region the land and
fresh-water shells of which were previously considered to be fairly
known. There can be no doubt, however, that in the Solomon Islands the
conchologist has much work that remains to be done. Not only are the
higher regions of the larger islands, entirely unexplored, but it would
appear from the collections made up to the present date in this large
group, that particular species may be not only confined to a special
sub-group of islands but may be restricted to a single island, and that
other species more widely distributed through the group may be
represented in each island and in different districts of the larger
islands by different varieties. Had I been aware of the extent of the
influence of locality in this region, I might have made my collection of
greater value. It would therefore seem necessary for future collectors
in this group to make in every small island and in different districts
of the larger islands special independent collections, disregarding the
fact that they may have apparently met with the same shell very
frequently before, because many of the varieties and some of the species
can only be distinguished by the practised eye of the specialist, and a
new locality for a previously well-known species may be often
unwittingly found.
[479] “On a collection of shells from the Solomon Islands” by Edgar
A. Smith. (Proceedings of the Zoological Society: June 2nd, 1885.)
This paper is illustrated with two coloured plates of the new
shells.
As an instance of the unexpected results, which may fall to the lot of
others in this group, I may here add, that out of eleven land and
fresh-water shells that I collected in the small island of Santa Anna,
which is only 2½ miles in length, four were new species, and besides
there were some new varieties. The stations of these four species may be
suggestive. Two of them--_Helix_ (_Videna_) _sanctæ annæ_ and _Helix_
(_nanina_) _solidiuscula_--were generally found on the trunks of the
cocoa-nut palms at the coast; whilst the other two occurred in
situations far more likely to yield new species, _Melania sanctæ annæ_
being obtained from a small stream in the interior of the island, and
_Melania guppyi_ being found dead in the stomach and intestines of a
fish that frequents the fresh-water lake of Wailava. This last shell
would appear to live in the deeper parts of the lake, as I only found
one living specimen, all the others being obtained from the stomach and
intestines of these fish. Mr. Smith describes it as “a very remarkable
and distinct species.” Its length is about 1⅕ inches; and its
sharp-pointed spire was to be sometimes seen protruding through the vent
of the fish, which evidently digests the animal and ejects the shell.
These fish were usually 9 or 10 inches long; but the full-grown shells
were found also in fish half this size, when the relation between the
length of the shell and the size of the fish was truly alarming. Since
the little fish actually swallow sharp pointed shells measuring a fifth
of their own length and pass them out through the vent after they have
digested the animal, we must credit them with a remarkable capacity for
adapting their diet to circumstances.
To exemplify the variation which some species of shells display in this
group, I will take the instance of _Helix_ (_Geotrochus_) _cleryi_,
Récluz. This species is probably distributed through the whole group;
but considerable variation prevails in different islands. Amongst the
several forms which I obtained, three were named as new varieties, var.
_meridionalis_ from Santa Anna, var. _simboana_ from Simbo or Eddystone
Island, and var. _septentrionalis_ from the islands of Bougainville
Straits, the localities of the two last varieties being only 80 miles
apart. Mr. Smith remarks that this species is “subject to considerable
variation in size, colour, and form, apparently resulting from
difference of habitat. . . . . . . . . Whether these several varieties
should take specific rank is questionable, for, although there is a
considerable difference between the extreme forms, even in the series of
nearly one hundred specimens under examination, the gradual transition
from one form to another is observable.”
Amongst the more singular in appearance of the land shells, I may refer
to the large _Bulimus_ (_B. cleryi_) which I found on the north coast of
St. Christoval. It attains a length of four inches. I was never able to
get a living specimen, as they are said by the natives to live in the
foliage of the high trees. The specimens which I obtained were empty
shells which the natives of the Koofeh district on the north coast of
St. Christoval are in the habit of throwing into heaps, each man when he
picks up a shell throwing it into the next heap he passes. I was unable
to learn the reason of this practice and the natives did not seem
willing to tell me. . . . Two other _Bulimi_ I commonly met with. One
was the pretty _Bulimus miltocheilus_ (Reeve), which, when the animal is
young and the shell delicate, has a greenish-yellow hue resembling the
colour of the leaves it feeds upon: as it grows older the shell becomes
thicker and stronger, and in proportion as there is less need for
protective resemblance, the greenish-yellow hue fades away, leaving a
dull white colour behind. This species is found in St. Christoval and
the adjacent islands. The other _Bulimus_ (_B. founaki_, Homb. Jacq.)
which I found in Faro Island, Bougainville Straits, and which had been
only previously obtained at Isabel Island, attains a length of rather
under three inches.
I come now to refer to the fresh-water shells of these regions. Stated
in their order of frequency, the _Neritinæ_, _Melaniæ_, and _Navicellæ_
are the common fresh-water shells of these islands. The _Neritinæ_ were
especially interesting to me. They abound in the streams: some of them
preferring the moist rocks above the water, others finding their home in
the waters of a quiet pool, whilst others, like the _Navicellæ_, prefer
to buffet the full rush of the torrent. An important feature with
reference to these fresh-water Nerites or _Neritinæ_ is their wide
dispersal. “Some of these species”--as Mr. Smith remarks in respect of
those in my collection--“range not only through most of the islands of
the Solomon Group, but have a considerably wider distribution.” Thus,
_Neritina subsulcata_ (Sowerby) and _N. cornea_ (Linné), are not only
found in the Solomon Islands, but also occur in the Philippines: _N.
macgillivrayi_ (Reeve) and _N. petiti_ (Récluz) alike exist in the Fiji
and in the Solomon Groups; while _N. porcata_ (Gould) has been found in
Samoa and in Fiji as well as in the opposite extremities of the group
with which I am at present concerned. Being interested in the question
of the mode of dispersal of these Nerites, I made the following
experiment to test their powers of sustaining submersion in salt-water.
One individual belonging to the species _Neritina subsulcata_[480]--a
species which is also found as above stated in the Philippines, and at
the same time is the most widely dispersed fresh-water Nerite in the
Solomon Group--survived a submersion of twelve hours; but not one out of
a dozen individuals was found alive after a submersion of five days,
although the water was changed from time to time. The result was a
surprise to me, as I inferred from the result of Baron Aucapitaine’s
experiments as related by Mr. Darwin,[481] that their close-fitting
stony _opercula_ would have enabled them to resist the action of
salt-water. Their death could have been scarcely due to want of food,
since I have kept shells of this species for several months on a very
scanty diet, and since the powers of endurance of other fresh-water
shells are well known. The matter passed out of my mind until after my
arrival in England, when Mr. Smith put the question to me, as to their
mode of dispersal. I then remembered that their calcareous egg-capsules,
which are so commonly seen on the rocky sides of the streams, are in all
probability sufficiently thick to resist the action of salt-water. Here
is therefore a probable mode of dispersal, and I see it is one which Mr.
Smith refers to as such in his paper. These egg-capsules “if attached to
floating timber, might be carried to considerable distances.” They are
often to be observed on the outside of the shells of living _Navicellæ_,
and I have seen them on the backs of the valves of a _Unio_ which I
discovered in the Shortland Islands.
[480] In his paper Mr. Smith refers to the species experimented on
as _N. cornea_: but in my own list he named a shell belonging to one
of the _Neritinæ_ in question as _N. subsulcata_.
[481] _Cyclostoma elegans_ was the species tested: _vide_ “Origin of
Species,” p. 353, 6th edit.
One common feature of these fresh-water shells, whether _Neritinæ_,
_Navicellæ_, or _Melaniæ_, is the extensive erosion of the apices and
surrounding parts of the shells. In some instances I have noticed that
almost the entire exterior of the shell has been extensively eroded,
particularly in the case of _Neritina subsulcata_, but I always found
that the erosion was greatest in non-calcareous districts, where the
free carbonic acid in the water is not all consumed in the solution of
the limestone rocks. In volcanic islands the erosion of the fresh-water
shells is greater than in islands of calcareous formation; and in
streams, which, like those of the north coast of St. Christoval, flow in
the upper portion of their course through a district of volcanic rocks
and in the lower portion through a district of calcareous rocks, the
same difference in the degree of erosion may be observed. I learn from a
recent work by Professor Semper[482] that it is the boring of a minute
fungus which first exposes the calcareous substance to the action of the
carbonic acid, and that the mechanical action of the stream in forming
tiny whirl-pools in the cavity probably assists in the erosion.
[482] “The Natural Conditions of Existence, etc:” London 1881: p.
212, circâ.
There are two common species of _Neritina_ in these islands which I
often confounded, viz., _N. subsulcata_ and _N. cornea_; and I learn
from Mr. Smith’s paper that these two species very closely approach each
other. They, however, are usually to be found in different stations, _N.
cornea_ occurring on the trunks of palms and other trees away from the
streams,[483] and _N. subsulcata_ preferring the moist rocky sides of
the streams a foot or so above the water.[484] Now and then they may be
found encroaching on each other’s domain; for I have found them together
on the trunks and branches of areca palms and tree-ferns in low lying
moist districts, whilst, as at Choiseul Bay, I found them together in
the streams.[485] Now it is a significant circumstance, that the
specimen of _N. cornea_ in my collection which was found by Mr. Smith to
make the nearest approach to _N. subsulcata_ was one which I obtained
from a stream in Choiseul Bay. It had, in this case, not only intruded
on the station of _N. subsulcata_, but had also assumed some of the
distinctive characters of that species. It, therefore, seems to me
probable that a graduated series of the shells of these two species
might be formed, which would present the stages of transition from the
one species to the other. If this be possible, then I would suggest that
the fresh-water Nerite (_Neritina subsulcata_) may have been transformed
into the tree Nerite (_Neritina cornea_) in the following manner.
[483] In St. Christoval I found this species on one occasion 150
feet above the nearest stream.
[484] This species often takes to the water. Some individuals that I
kept alive on board used to spend a quarter of an hour at a time in
the water eating voraciously all the while.
[485] According to Prof. Semper, these two species in the
Philippines live a large portion of the year high up on the trees in
mangrove swamps. (Ibid.)
I have already referred to the circumstance that in the higher portions
of the St. Christoval streams, where the rocks are entirely volcanic,
the fresh-water shells--and I may here add, especially those of
_Neritina subsulcata_--suffer much more erosion than do shells of the
same species in the lower parts of the streams where they flow through
calcareous districts. Now, the geological structure of this island being
mainly ancient volcanic rocks incrusted near the coast by recent
calcareous formations, the time will come when these calcareous
envelopes will have been entirely stripped off by denudation. How this
will influence the Nerites of the streams may be thus explained. At
present the normal characters of the species are preserved in the
calcareous portions of the streams; but when all the calcareous rocks
have been stripped off by denudation, the Nerite through its whole
lifetime will be subjected to that extensive process of erosion, which
now often denudes almost the entire surface of the shells of those
individuals that live in the volcanic portion of the stream’s course.
Here, Natural Selection may step in to favour the survival of any slight
variation that makes the Nerite more suited to lead an entirely arboreal
existence. Such a geological agency may in truth lead finally to the
expulsion of the Nerite from the stream’s course. Varieties will survive
only in proportion to their capability of adapting themselves to the new
condition; and they alone will perpetuate their kind until a tree Nerite
of distinct specific character is produced. . . . . On this reasoning,
tree Nerites ought to be more numerous in islands of volcanic formation;
but this is a point on which I cannot pronounce from the lack of
sufficient evidence.[486]
[486] Prof. Semper’s observations in the Philippines bear on this
matter. (“Natural Conditions of Existence,” &c., p. 188.)
According to Professor Semper, we have in _Navicella_ “a modified form
of _Neritina_,” which genus it resembles in all essential anatomical
characters, but “by long inurement to living in rushing mountain
streams, it has had its shell modified in the way most suited to those
conditions, while the _operculum_, in consequence of long disuse, has
become a peculiar degenerate or rudimentary organ.”[487]
[487] Ibid, p. 212.
The growth of the fresh-water Nerites would appear to be slow. I kept a
young individual of _Neritina subsulcata_ for seven months in a bottle
partly filled with rain-water, and supplied it with decaying leaves for
food which it used to eat. Its weight was 37 grains both at the
beginning and the end of the experiment, having only varied half a grain
during the whole time; and its dimensions, as determined by measurement,
were unaltered. This species, when it is first picked off the rock,
ejects a watery fluid with a powerful musky odour, which effect
accompanies the closure of the shell by the _operculum_. I kept some
individuals of this species in rain-water, containing varying
proportions of lime-water, for about three months. The lime-water was of
the medicinal strength of the British Pharmacopeia. I began with water
containing 64 parts of rain-water to one part of the lime-solution. By
the end of the first month the proportion was increased to 32 to 1; by
the end of the second month it was 16 to 1; towards the end of the third
month the Nerites, having lived for over three weeks in the last
solution, began to die; the survivors were placed in a solution
containing the proportion of 8 to 1, but this amount of the
lime-solution proved too much for them. It should be remarked that
throughout the experiment, the Nerites used to descend to the water to
get their food just as frequently as in the state of nature: they did
not avoid the water; and after the experiment was over, there was no
apparent alteration in the appearance of the shells. These observations
were made in the north part of New Zealand during the latter part of the
summer and the beginning of the autumn, a circumstance which may
partially explain the death of the shells. The temperature there was
about 20° below the temperature they are accustomed to in the Solomon
Islands; this difference is of interest when it is remembered that
_Neritinæ_ are mostly found in the streams of tropical regions; and I
may, therefore, infer that this species is capable of adapting itself to
temperatures much lower than that to which it is accustomed, since some
individuals survived the voyage to New Zealand from the Solomon Islands
and lived in the climate of the former region for three months under
very unfavourable conditions.
Professor Semper[488] remarks that some _Neritinæ_ have the habit of
detaching themselves from rocks on the slightest touch, by this means,
as he considers, escaping the pursuit of their enemies. Some of them,
however, as I observed, detach themselves spontaneously and
independently of any alarm. The individuals of _Neritina subsulcata_
that I kept in a large bottle in my cabin, used frequently in the course
of a night to detach themselves from the sides and drop down into the
water below. On one occasion when the noise woke me up, I found the
culprit voraciously eating a portion of decayed leaf. In the daytime
they sometimes dropped, and at other times crawled, down to the water.
. . . . . It is probable that the musky water, which this Nerite ejects
when it is picked off a rock, may cause a bird to drop it from its beak
and thus save its life.
[488] Ibid, p. 210.
Amongst the new fresh-water shells that I found in this group was a
species of _Unio_, to which Mr. Smith did me the honour of attaching my
name, it being the first species of this genus of river-mussels that has
been found in the Solomon Group. But its occurrence there means
something more than a new locality, since, as I believe, I am correct in
asserting, we have in it the first record of this widely distributed
genus having reached the Pacific islands. I do not think that this
species can be generally spread through the Solomon Group. I only found
it in one locality, namely the Shortland Islands, near the western end
of the group.
A very familiar shell, in low-lying moist and marshy situations
throughout the Solomon Islands, is that of the auriculoid, _Pythia
scarabæus_, Linné. Being usually accustomed to find it in the low-lying
districts, I was surprised on one occasion to find it in the higher
parts of Faro Island, which attains an elevation of 1,900 feet above
sea. In the mangrove swamps and in the lower parts of the streams at
Choiseul Bay, I found a species of _Cyrena_ which has not yet been
described, together with _Cerithidea cornea_ (A. Adams: var.) and
_Pyrazus palustris_, the last species occurring also in India. On the
moist ground of the taro patches in the islands of Bougainville Straits
thrives a species (_S. simplex_, var.) of that ubiquitous genus
_Succinea_. The operculated land-snails, of which the _Helicinæ_ are the
most numerous, are found more frequently in calcareous districts.
LIST OF LAND AND FRESH-WATER SHELLS COLLECTED IN THE SOLOMON
ISLANDS[489] DURING 1882 AND 1883. (EXTRACTED FROM MR. E. SMITH’S PAPER
IN THE PROCEEDINGS OF THE ZOOLOGICAL SOCIETY OF LONDON, JUNE, 2ND,
1885.) THE DESCRIPTIONS OF THE NEW SPECIES AND VARIETIES FOLLOW:
[489] The habitats given are confined to the Solomon Group. I have
added the new habitats of species in my collection to those
previously ascertained from the collections of Brenchley,
Macgillivray, Hombron and Jacquinot, etc.
(1) _Helicarion planospira_ (Pfeiffer) _Hab._ Santa Anna, Ugi, St.
Christoval, Guadalcanar.
(2) _Helix_ (_Nanina_) _nitidissima_ (nov. spec.) _Hab._ Treasury
Island, a variety in Guadalcanar.
(3) _Helix_ (_Nanina_) _solidiuscula_ (nov. spec.) _Hab._ Santa
Anna, found generally on the trunks of cocoa-nut palms.
(4) _Helix_ (_Corasia_) _tricolor_ (Pfeiffer) _Hab._ St. Christoval,
Ugi, Santa Anna.
(5) _Helix_ (_Corasia_) _anadyomene_, A (Adams & Angas) _Hab._
Guadalcanar, Ugi.
(6) _Helix_ (_Geotrochus_) _acmella_ (Pfeiffer) _Hab._ Faro Island,
Bougainville Straits; Florida Islands, _vide_ original paper.
(7) _Helix_ (_Geotrochus_) _gamelia_ (Angas) _Hab._ Isabel, Stephen
Island, Shortland Islands, Treasury Island, Choiseul Bay.
(8) _Helix_ (_Geotrochus_) _hargreavesi_ (Angas) _Hab._ Faro Island
in Bougainville Straits.
(9) _Helix_ (_Geotrochus_) _mendana_ (Angas) _Hab._ Shortland
Islands, _vide_ original paper.
(10) _Helix_ (_Geotrochus_) _motacilla_ (Pfeiffer) _Hab._ Simbo or
Eddystone Island, also called Narovo.
_Note._--In the original paper, Simbo and Eddystone are referred to
as two different islands. This mistake arose from the omission of
the name of Simbo in the latest charts; it is, however, the name
usually employed.
(11) _Helix_ (_Geotrochus_) _guppyi_ (nov. spec.) _Hab._ Faro Island
in Bougainville Straits.
(12) _Helix_ (_Geotrochus_) _dampieri_ (Angas) var. _Hab._ Choiseul
Bay.
(13) _Helix_ (_Geotrochus_) _eros_ (Angas) _Hab._ Isabel, Stephen
Island, Shortland Islands.
(14) _Helix_ (_Geotrochus_) _cleryi_ (Récluz) _Hab._ Santa Anna,
Ugi, St. Christoval, Guadalcanar, Rua Sura Islets, New Georgia,
Simbo or Eddystone, Treasury, Shortlands, Choiseul Bay. Three new
varieties, var _meridionalis_ (Santa Anna), var _simboana_ (Simbo or
Eddystone), var _septentrionalis_ (Shortlands, Treasury, Choiseul
Bay.)
(15) _Helix_ (_Videna_) _merziana_ (Pfeiffer) _Hab._ St. Christoval,
New Georgia, Ugi; _vide_ original paper.
(16) _Helix_ (_Videna_) _sanctæ annæ_ (nov. spec.) _Hab._ Santa
Anna, living on the trunks of cocoa-nut palms.
_Note._--This species, or a closely similar form, was observed by me
in many other islands; but I neglected to collect it in any other
locality than Santa Anna.
(17) _Helix_ (_Rhytida_) _villandrei_ (Gassies) _Hab._ St.
Christoval, Ugi.
(18) _Helix_ (_Camæna_) _hombroni_ (Pfeiffer) _Hab._ Shortland and
Faro Islands in Bougainville Straits, Isabel.
(19) _Helix_ (_Chloritis_) _eustoma_ (Pfeiffer) _Hab._ New Georgia,
Ugi, Faro Island (Bougainville Straits.)
(20) _Bulimus_ (_Placostylus_) _cleryi_ (Petit) _Hab._ St.
Christoval.
(21) _Bulimus_ (_Placostylus_) _founaki_ (Hombron and Jacquinot)
_Hab._ Isabel, Faro Island (Bougainville Straits).
(22) _Bulimus_ (_Placostylus_) _miltocheilus_ (Reeve) _Hab._ St.
Christoval (S.E. part), Ugi, Santa Anna: _vide_ original paper.
(23) _Partula_, spec. _Hab._ Guadalcanar, Ugi, Treasury Island,
Choiseul Bay: _vide_ original paper.
(24) _Succinea simplex_ (Pfeiffer) var. _Hab._ Treasury Island,
Shortland Islands: living on the moist ground in the taro patches.
(25) _Cyclostoma_ (_Adelostoma_) _triste_ (Tapparone Canefri), var?
_Hab._ Guadalcanar; Santa Anna; Faro and Shortland Islands and
Choiseul Bay in Bougainville Straits.
(26) _Leptopoma jacquinoti_ (Pfeiffer) _Hab._ Rua Sura Islets off
the north coast of Guadalcanar: _vide_ original paper.
(27) _Leptopoma vitreum_ (Lesson) _Hab._ Santa Anna, Simbo or
Eddystone; Shortland Islands.
(28) _Omphalotropis nebulosa_ (Pease) _Hab._ St. Christoval,
Guadalcanar, Ugi. I found this shell living on trees clothing a low
tract of land skirting the beach.
(29) _Pupina solomonensis_ (nov. spec.) _Hab._ Shortland and
Treasury Islands in Bougainville Straits: living in the decayed
trunks of fallen trees.
(30) _Hargravesia polita_, H. (Adams), var. _Hab._ Faro Island in
Bougainville Straits: _vide_ original paper.
(31) _Helicina moquiniana_ (Récluz) _Hab._ St. Christoval,
Guadalcanar, Ugi.
(32) _Helicina egregia_ (Pfeiffer) _Hab._ Guadalcanar, Florida
Islands.
(33) _Helicina modesta_ (Pfeiffer) _Hab._ Guadalcanar, Shortland
Islands, Treasury Islands, Choiseul Bay.
(34) _Helicina solomonensis_ (nov. spec.) _Hab._ The Islands of
Bougainville Straits (Faro, Shortlands, Treasury).
(35) _Pythia scarabæus_ (Linné) _Hab._ Santa Anna, St. Christoval,
which were the localities of my specimens; but I observed this
species and its varieties in every island I visited. _Stat_: Moist
ground usually near the sea.
(36) _Melampus fasciatus_ (Deshayes) _Hab._ Isabel, Rua Sura Islets
off the north coast of Guadalcanar. I found these shells in the
crevices of a log on the beach.
(37) _Melania amarula_ (Linné) _Hab._ Ugi, in the streams.
(38) _Melania scabra_ (Müller) _Hab._ Ugi, in a stream.
(39) _Melania salomonis_ (Brot.) _Hab._ Ugi, in a stream.
(40) _Melania fulgurans_ (Hinds) _Hab._ Ugi, in a stream.
(41) _Melania fastigiella_ (Reeve) _Hab._ Imbedded in a dark
calcareous loam exposed in the banks of a large stream near its
mouth at Sulagina, on the north coast of St. Christoval. I could not
find any living specimens.
(42) _Melania_ spec. _Hab._ The same as _Mel. fastigiella_.
(43) _Melania verrucosa_ (Hinds) _Hab._ The same as _Mel.
fastigiella_.
(44) _Melania subgradata_ (nov. spec.) _Hab._ The same as _Mel.
fastigiella_.
(45) _Melania ugiensis_ (nov. spec.) _Hab._ From a stream in Ugi.
(46) _Melania sanctæ annæ_ (nov. spec.) _Hab._ A stream in the
interior of Santa Anna.
(47) _Melania guppyi_ (nov. spec.) _Hab._ From the stomach and
intestines of a fish living in the fresh-water lake of Wailava in
the island of Santa Anna. This species probably frequents the deeper
parts of the lake, as I only found one living individual.
(48) _Cerithidea cornea_ A. (Adams) var. _Hab._ Mangrove swamps in
Choiseul Bay.
(49) _Pyrazus palustris_ _Hab._ Mangrove swamps in Choiseul Bay.
_Note._--Not referred to in original paper.
(50) _Nerita marmorata_ (Hombron and Jacquinot) _Hab._ Living just
above high-water level on the surface of the coral-limestone coast,
St. Christoval.
(51) _Neritina cornea_ (Linné) _Hab._ Star Harbour, St. Christoval,
on the trunks of trees 150 feet above the nearest stream; Choiseul
Bay, from a stream; Shortland Islands, on the stems of tree-ferns
and areca palms in a marshy district. I found this species in many
other islands; but did not collect it except in the above three
localities.
(52) _Neritina subsulcata_ (Sowerby) _Hab._ Streams in St.
Christoval and in the islands of Bougainville Straits. In the
Shortland Islands I found this species on the stems of tree-ferns
and areca palms in a marshy district. I only collected it in these
localities; but I found it in many other islands. When first picked
off the rock, it ejects a watery fluid possessing a powerful musky
odour.
(53) _Neritina dubia_ (Chemnitz) _Hab._ Shortland Islands, in a
stream.
(54) _Neritina adumbrata_ (Reeve) _Hab._ A stream in Choiseul Bay,
and the rocky sides of a stream-course in Ugi.
(55) _Neritina pulligera_ (Linné) _Hab._ Guadalcanar, St.
Christoval, Ugi, Choiseul Bay, in the streams.
(56) _Neritina petiti_ (Récluz) _Hab._ Treasury and Faro Islands, in
the streams.
(57) _Neritina olivacea_ (Le Guillou) _Hab._ Streams in Treasury
Island and at Sulagina, St. Christoval.
(58) _Neritina macgillivrayi_ (Reeve) _Hab._ Streams in Guadalcanar
and in Faro Island, Bougainville Straits.
(59) _Neritina asperulata_ (Récluz) _Hab._ Rocky sides of a
stream-course in Ugi.
(60) _Neritina porcata_ (Gould) _Hab._ St. Christoval, and Faro
Island, Bougainville Straits, in streams.
(61) _Neritina variegata_ (Lesson) _Hab._ St. Christoval, Ugi; Simbo
or Eddystone; Faro Island, Bougainville Straits; Choiseul Bay; in
streams.
(62) _Neritina turtoni_ (Récluz) _Hab._ A stream in the Shortland
Islands; streams in Guadalcanar; imbedded in a dark calcareous loam
exposed in the banks of a large stream near to its mouth at Sulagina
on the north coast of St. Christoval.
(63) _Neritina brevispina_ (Lamarck) _Hab._ Streams in Shortland,
Treasury, and Ugi Islands. The specimens from Treasury Island were
destitute of spines.
(64) _Neritina squarrosa_ (Récluz) _Hab._ Streams in Treasury
Island.
(65) _Navicella sanguisuga_ (Reeve) _Hab._ Streams in Faro Island,
Bougainville Straits.
(66) _Navicella suborbicularis_ (Sowerby) _Hab._ Guadalcanar, St.
Christoval, Ugi, Treasury and Faro Islands in Bougainville Straits.
(67) _Unio guppyi_ (nov. spec.) _Hab._ Streams in the Shortland
Islands.
(68) _Cyrena_, spec. _Hab._ In the lower parts of streams and in
mangrove swamps, Choiseul Bay. _Note._--This species is not referred
to in the original paper.
_Descriptions of the new species and varieties_,[490] by Mr. E. Smith.
[490] The numbers refer to the plates in Mr. Smith’s paper (Proc.
Zool. Soc., June 1885).
(2) _Helix_ (_Nanina_) _nitidissima._ (Plate XXXVI. figs. 1, 1 _b_.)
Shell thin, transparent, very glossy, depressed, narrowly perforate,
pale brownish horn-colour above, whitish towards the umbilicus,
sculptured with very faint lines of growth. Whorls 4-5, slightly
convex, impressed and marginate above at the suture; last whorl
large, rounded at the periphery. Aperture obliquely lunate;
peristome simple, thin, slightly thickened and reflexed partly over
the perforation. Spire low, but very little raised above the last
whorl, obtuse at the apex. Greatest diameter 14 millim., smallest
12; height 9.
(3) _Helix_ (_Nanina_) _solidiuscula._ (Plate XXXVI., figs. 2, 2
_b_.) Shell very narrowly perforate, depressed, somewhat solid, dark
chestnut-brown and a little glossy above, more shining and paler
beneath, becoming almost white at the umbilical region; whorls 6½,
convex, separated by a deepish suture, and, with the exception of
two or three at the apex which are smooth, sculptured with strong,
close-set, arcuate, and oblique striæ on the upper surface, crossed
with a few more or less distinct spiral lines. Body-whorl rounded at
the periphery, or sometimes with the faintest indication of an
angle, convex, and only exhibiting fine lines of growth below.
Aperture obliquely semi-lunate; peristome simple, but, owing to the
solidity of the shell, seeming slightly thickened, especially on the
very oblique columellar margin, which is shortly reflexed above over
the perforation. Spire depressed-conoid, having the least convex
outlines and an obtuse apex. Greatest diameter 18 millim., smallest
16½, height 12; aperture 8 long, 4½ wide.
This species is well distinguished by its comparative solidity and
strong sculpture on the upper surface.
(4) _Helix_ (_Corasia_) _tricolor_ (Pfeiffer). (Plate XXXVI., figs.
3, 3 _b_.) A specimen obtained on the north coast of the same island
of St. Christoval, by Mr. Guppy, is worthy of special mention, and
may be termed var. _picta_, on account of the undulating
reddish-brown stripes which ornament both the upper and lower
surfaces.
A similar example was also collected by Dr. A. Corrie and presented
to the Museum. The markings on these two shells are very striking
and distinctly visible within the aperture.
(11) _Helix_ (_Geotrochus_) _guppyi._ (Plate XXXVI. fig. 4.) Shell
elevately conical, thin, pale yellow, ornamented with conspicuous
nearly black or black-brown spiral bands, one above and one below
the sutures of the upper whorls, and three upon the last, one
sutural, the second peripheral, and the third basal. Volutions 6,
rather slowly enlarging, a little convex, sculptured with fine
oblique striæ of growth, not glossy. Three first whorls livid
purplish, the last rather sharply angled at the middle, not
descending in front, having the basal band broad around the almost
concealed perforation, and obsolete within the aperture. The latter
is oblique, somewhat narrowed and pouting in front, banded within
with three almost black and two white bands, the central one of the
former being squarely truncate at the end, only the lower corner of
it touching the margin of the lip, which is pale oblique, receding,
a little expanded and reflexed in front and at the columellar
margin, the upper end of which is spread over and nearly conceals
the small umbilicus. Height 22½ millim., greatest diameter 19,
smallest 16.
This species is remarkable for the striking contrast of its
colour-bands and the angular character of the last whorl.
(12) _Helix_ (_Geotrochus_) _dampieri_, Angas, var. (Plate XXXVI.
fig. 5.) Shell imperforate, subglobose, conoid, light brown or
fawn-colour, here and there minutely dotted with dark-grey specks,
with a broad white band around the middle of the penultimate whorl
and two upon the last, one above and the other below the middle,
also a narrow white line revolving up the spire beneath the suture,
and a dark brown zone surrounding the pale or yellowish umbilical
region. Whorls 5, a little convex above, somewhat glossy, obliquely
and very finely striated by the lines of growth, the last more or
less concentrically striated beneath, shortly descending at the
aperture which is white within. Lip a little thickened, edged with
reddish brown, only slightly expanded on the right side, more
dilated below, produced into a thin transparent callosity over the
umbilical region, united above to the upper extremity of the
peristome. Columellar margin oblique, white or partly tinged with
reddish brown, thickened and terminating below within the edge of
the lip. Height 19 millim., greatest diam. 22, smallest 19.
The specimens from the Solomon Islands are smaller than the type
with which, through the kindness of Mr G. F. Angas, I have compared
them. They also have the peristome brown, and the basal band is
darker.
(14) _Helix_ (_Geotrochus_) _cleryi_, Récluz (Plate XXXVI. figs 6, 6
_b_). The specimens from Santa Anna (var. _meridionalis_ fig. 6 _b_)
are smaller than the type, pale brown above, with a white
thread-like line at the suture, and the acutely keeled periphery,
paler beneath, especially towards the centre, and have the aperture
particularly acuminate at the termination of the keel.
The specimens from Simbo (var. _simboana_, fig. 6 _a_) are uniformly
pale horn-colour, rather sharply carinate at the middle, and have
the peristome white, considerably thickened and almost notched at
the upper end of the columella, and the body-whorl is more
contracted than in the typical form. The examples from Choiseul Bay,
Shortland and Treasury Islands (var. _septentrionalis_, fig. 6) are
all alike, of smaller dimensions than the normal form, thin pale
brownish horn-colour, with rather more convex whorls than usual, the
carina at the periphery being acute and thread-like as in the
variety _simboana_.
Whether these several varieties should take specific rank is
questionable, for, although there is considerable difference between
the extreme forms even in the series of nearly one hundred
specimens under examination, the gradual transition from one form
to another is observable.
(16) _Helix_ (_Videna_) _sanctæ annæ._ (Plate XXXVI. figs. 7. 7
_b_.) Shell depressed-conoid, deeply umbilicated, very acutely
keeled at the periphery, light brown, sometimes with a few radiating
pale streaks on the upper surface, sculptured with oblique lines of
growth. Whorls 5, rather slowly increasing, slightly convex,
depressed and margined above the suture, last not descending,
compressed above and below the keel, a little convex towards the
umbilicus, which is moderately large. Aperture transverse,
flesh-tinted within. Peristome simple, a little thickened along the
basal margin, with the extremities united by a thin callus. Height 7
millim.; greatest diameter 17, smallest 15.
(25) _Cyclostoma_ (_Adelostoma_) _triste_, Tapparone Canefri, var.?
Dr. Tapparone Canefri has kindly compared specimens from these
islands with his _C triste_, and is of opinion that they may be
considered a variety of it; and observes that the New-Guinean form
is a little smaller, its spire a little more slender, its surface
more glossy, the colour redder, and the apex of the spire darker.
The shells under examination are clothed with a very thin epidermis
when in a fresh condition, exhibiting numerous very fine spiral
thread-like lines, which entirely disappear in worn shells and can
easily be rubbed off with a brush. For several species having a
similar epidermis and an incomplete peristome, Dr. Tapparone Canefri
has proposed the subgenus _Adelostoma_.
(29) _Pupina solomonensis._(Plate XXXVI. fig. 9, 9 _a_.) Shell small
and very like _P. difficilis_, Semper, and _P. keraudreni_, Vignard.
It is of a reddish tint, especially the body-whorl; consists of 5½
whorls, which are the least convex and exhibit a pellucid line,
frequently brown, immediately beneath the suture. Last whorl very
obliquely descending behind, narrowed below, and flattened somewhat
above the aperture. Columella thickened with callus, white, parted
off from the whorl above by an oblique circumscribing red line,
truncated rather low down. Outer lip slightly thickened and effuse,
and a little paler than the rest of the whorl, produced somewhat at
its junction with the body-whorl, which in consequence has the
appearance of rising suddenly after an oblique descent. Length 7
millims., diam. 3⅔, aperture 2 long and wide.