bright scarlet orange; basal edges of the scuta, and sometimes of all
the valves, with a torn border of orange membrane. Interspaces between
the valves dull orange-brown. Peduncle darkish purplish-brown, with the
lower part sometimes pale; chitine membrane itself tinted orange; in
young specimens, peduncle pale, the colour first appearing in the
uppermost part, close under the capitulum; this upper part is often
darker than the other parts, and never orange-coloured, as in _L.
Hillii_ and _L. anserifera_. _Sack_ internally dark purplish
lead-colour, sometimes with a tinge of orange, darkest under the
growing edges of the valves; body of animal pale purplish lead-colour.
The four posterior cirri blackish purple; the second, and often the
third cirrus, appear as if the colour had been laterally abraded off;
these latter cirri have sometimes a tinge of orange. In very young
specimens, the cirri are only barred with purple. The ova and the
contents of the ovarian tubes are of a beautiful azure blue, becoming
yellow in spirits.
In museums a vast amount of difference is seen in the colours of this
species, caused by the method of preparation: if dried without having
been in spirits, and subsequently kept dry, the orange tint round the
orifice is preserved; if kept long in spirits, this is quite lost; but
sometimes in specimens in spirits the colour of the membrane of peduncle
is preserved and rendered pinker. The colours of the sack and animal are
either quite discharged or rendered extremely dark. The valves
themselves also often become more opaque. In some specimens well
preserved in spirits, the sack and cirri were purplish-brown or
lead-colour, tinted with dirty green, or orange, or bright yellow, or
brick-red.
_General Remarks._--From the foregoing description it will be seen how
extremely variable almost every part of this species is. I find, in the
British Museum, ten distinct specific names given by Dr. Leach to
different varieties, or rather to different specimens, for some of them
are undistinguishable. A specimen from the Sandwich Islands, sent by Mr.
Conrad to Mr. Cuming, is marked _A. engonata_.
In looking over a large collection of specimens in a museum, the most
distinctive characters appear at first to be the colours, the dentation
or barbed condition of the carina, the row of square marks on the scuta
and terga, and the more or less produced form of the whole capitulum:
all these characters are absolutely worthless as distinctive characters,
and blend into each other. In a fresh condition, the colours of this
species, and of _L. anserifera_ and _L. Hillii_ are surprisingly alike,
though in _L. anatifera_ alone, the uppermost part of the peduncle is
dark. As far as I have seen, the smoothness of the valves, together with
the presence of a tooth beneath the umbo, on the right-hand scutum, and
its entire absence on the left side, (in other species it is smaller on
this, than on the right-hand side,) is an unfailing diagnostic mark. I
believe this species is always attached to floating objects, though
there are some very young specimens in the British Museum, collected by
Sir G. Grey, adhering to sandstone, but this may have been buoyed up by
some large sea-weed. Mr. Peach has given me the particulars of two
instances, in which, after gales of wind, this species, of nearly full
size, adhering to _apparently_ freshly broken-off Laminariæ, has been
cast upon the coast of England and Scotland.
2. LEPAS HILLII. (Pl. I, fig. 2).
ANATIFA vel PENTALASMIS LÆVIS (!) plerumque auctorum.
PENTALASMIS HILLII (!). _Leach._ Tuckey’s Congo Expedit. p. 413,
1818.
---- CHELONIÆ (!) Ib. Ib.
ANATIFA TRICOLOR (?). _Quoy_ et _Gaimard_. Ann. des Sc. Nat., 1st
series, tom. x, 1827, Pl. vii, fig. 7, et Voyage de
l’Astrolabe, Pl. xciii, fig. 4.
---- SUBSTRIATA (!). _Conrad._ Journal Acad. Nat. Sc.,
Philadelphia, vol. vii, 1837, p. 262, Pl. xx, fig. 14.
_L. valvis lævibus; scutorum dentibus internis umbonalibus nullis;
carinâ à cæteris valvis, furcâ etiam a scutorum basali margine, paululum
distante; pedunculi parte superiore aut pallidâ aut aurantiacâ._
Valves smooth; scuta destitute of internal umbonal teeth; carina
standing a little separate from the other valves, with the fork not
close to the basal margin of the scuta; uppermost part of peduncle
either pale or orange-coloured.
Filaments three on each side.
Extremely common; attached to ships’ bottoms, from all parts of
the world; on floating timber; associated with _L. anatifera_
and _L. anserifera_. Mediterranean. Attached to turtles, in the
Atlantic, lat. 30° north. West Indies. Falkland Islands. “South
Seas,” collected by A. Menzies. Port Stephen, Australia.
_General Appearance._--Capitulum laterally flat; length varies in
proportion to the breadth; valves white, somewhat translucent,
moderately thick, very smooth, but with faint traces of radiating lines;
in some varieties, surface rather irregular along the zones of growth.
_Scuta_ without any internal teeth, and with scarcely any trace of the
internal basal rim; upper angle little acuminated; the occludent margins
of the two scuta stand rather separate from each other, showing a wide
space of corium between them: these margins are arched and protuberant,
but with the lower part a little hollowed out; basal margin a little
curved. In one specimen alone, I saw a trace of a diagonal line of
square coloured marks, like those common in _L. anatifera_. _Terga_
rather broad, with the basal angle not much acuminated. The degree of
prominence and outline of the double occludent margin varies very much.
_Carina_, separated by a rather wide space from the scuta and terga; of
very varying shape, the upper part not much acuminated, generally very
flat, sometimes exteriorly marked by a central depressed line; never
barbed; occasionally, (in a specimen from Australia,) middle part so
wide as almost to become spoon-shaped; on the other hand occasionally of
nearly the same width throughout; somewhat constricted above the fork.
Fork deeply embedded as usual; situated, in fresh specimens, a little
way beneath the basal margins of the scuta, instead of touching them, as
in the other species; forks of varying width, not so abruptly inflected
as in many species; sometimes much narrower than the upper widest part
of the valve, sometimes nearly twice as wide; prongs of fork not very
sharp, diverging at about a right angle, with the rim between them
reflexed. The apex of the carina extends up between the terga for barely
half their length, instead of up fully three fourths of their length,
as in _L. anatifera_.
The chitine membrane at the base of the capitulum, especially at the
anterior and posterior ends, is covered with beautiful, little,
embedded, yellowish beads, about 3/2000th of an inch in diameter; above
this, on each side of the carina, there is a space with similar but
smaller little spheres, and still higher up still minuter ones; others
occur on different parts of the capitulum; these spaces are seen to be
distinctly separated from each other, and present a beautiful appearance
under a high power.
_Peduncle_, as long as, or rather longer than, the capitulum: in one set
of specimens, however, it was thrice or four times as long as the
capitulum. The peduncle, in some specimens, was conspicuously covered
with transverse plates of yellowish hard chitine.
_Filamentary Appendages._--Three on each side; one on the flank of the
prosoma, with a pair beneath the basal articulation of the first cirrus;
relative lengths various, but the posterior filament of the pair under
the cirrus, is the shortest. _Mouth_; palpi not much acuminated; maxillæ
step-formed, but with the upper or first step in some specimens
indistinct, or forming a curve. _Cirri_; the segments of the first
cirrus and of the posterior arm of the second cirrus are highly
protuberant, the protuberances sometimes equalling half the thickness of
the segments themselves. Caudal appendages smooth, rounded.
_Size._--The largest specimen which I have seen, in the collection of
Mr. Cuming, had a capitulum 1-1/10th of an inch long, and 1-1/4 wide;
therefore not quite equalling in size the largest specimens of _L.
anatifera_.
_Colours._--When fresh, valves blueish-grey from the underlying corium,
edges of all the valves and round the orifice, and round the top of the
peduncle, bright orange-yellow, passing into the finest scarlet, and
varying slightly in tint in different specimens. Space between the
carina and the other valves, and between the occludent margins of the
scuta, rich purplish-brown; peduncle either pale or purplish-brown, or
only clouded on the sides with the same. In young specimens, peduncle
nearly colourless; and in those under a quarter of an inch long in the
capitulum, the top of the peduncle has not acquired its orange tint.
Sack pale, leaden-purple, body the same, but paler and more reddish;
cirri (but only the tips of first pair) tinted with fine golden orange.
Immature ova in peduncle beautiful blue. After being long kept in
spirits, the colours are changed, weakened, or discharged, as in _L.
anatifera_ and _L. anserifera_, and the valves become opaque. In some
long-kept specimens the corium everywhere had become pale brown; more
usually it assumes a dirty purplish lead-colour.
_Monstrous Variety._--Amongst a set of ordinary specimens from a ship
from Genoa, sent me by Mr. Stutchbury, there were three, one full-grown
and two very young, with the whole capitulum, (and likewise with the
scuta and terga taken separately,) not above half the usual length in
proportion to the breadth. Neither the colours nor animal in this
variety presented any difference.
_General Remarks._--This species is almost universally confounded with
_L. anatifera_. Quoy and Gaimard, however, appear to have distinguished
it, under the name of _A. tricolor_, from its colours. Leach named it
accidentally, for he specifies not one distinctive character, and
besides his two published names, he has appended two other names to
specimens in the British Museum. A specimen, from the Sandwich Islands,
sent by Mr. Conrad to Mr. Cuming, is marked _A. substriata_. In a dry
state, from the shrinking of the membranes, and consequent approach of
the carina to the other valves, and of the fork to the basal margin of
the scuta, it is most difficult to distinguish this species, though so
decidedly distinct, from _L. anatifera_; the absence, however, of a
tooth on the under side of the right-hand scutum is at once
characteristic. Even in specimens kept in spirits, in which there has
been no shrinking, but in which the colours have changed, and taking
into account the variation in the carina and upper part of the terga,
this species is not always readily distinguished from _L. anatifera_,
without opening the valves and looking for the right-hand tooth of the
latter. In fresh specimens, the orange ring at the top of the peduncle,
and the broad purplish interspace between the carina and other valves,
are characteristic. In all states, the filamentary appendages offer a
good character.
3. LEPAS ANSERIFERA. Pl. I, fig. 4.
L. ANSERIFERA. _Linnæus._ Syst. Naturæ, 1767.
ANATIFA STRIATA. _Brug._ Encyclop. Meth. (des vers), Pl. clxvi,
fig. 3.
PENTALASMIS DILATATA! (young). _Leach._ Tuckey’s Congo Expedit.,
p. 413, 1818.
ANATIFA SESSILIS (?). _Quoy et Gaimard._ Voyage de l’Astrolabe,
Pl. xciii, fig. 11.
LEPAS NAUTA.[27] _Macgillivray._ Edin. New Phil. Journ., vol.
xxxviii, p. 300.
PENTALASMIS ANSERIFERUS. _Brown._ Illust. Conch., 1844, Pl. li,
fig. 1.
[27] Professor Macgillivray does not consider the species, which
he has described under _L. nauta_, and which I cannot doubt is
the same with the present species, as the _L. anserifera_ of
Linnæus; but I find it so named in all old collections, and it
seems to agree very well with Linnæus’s description. There has
been much groundless confusion about this species; I have no
hesitation in giving _A. striata_, of Brugière, as a synonym,
though I have received from Paris the _Lepas pectinata_ of this
volume, named as the _A. striata_; and on the other hand, Poli
has incorrectly called a common variety of _L. pectinata_ by the
name of _L. anserifera_.
_L. valvis approximatis leviter sulcatis (tergis præcipuè); scuto dextro
dente forti interno umbonali, lævo aut dente exiguo, aut merâ cristâ
instructo; margine occludente arcuato, prominente: pedunculi parte
superiore aurantiacâ._
Valves approximate, slightly furrowed, especially the terga; right-hand
scutum with a strong internal umbonal tooth; left-hand with a small
tooth, or mere ridge; occludent margin arched, protuberant: uppermost
part of peduncle orange-coloured.
Filaments five or six on each side.
Var. (_dilatata_, young); valves rather thin, finely furrowed, often
strongly pectinated; scuta broad, with the occludent margins much
arched, making the space wide between this margin and the ridge
connecting the umbo and the apex: carina often barbed.
Common on ships’ bottoms from the Mediterranean, West Indies,
South America, Mauritius, Coast of Africa and the East-Indian
Archipelago. Central Pacific Ocean. China Sea. Chusan. Sydney.
Attached to pumice, various species of fuci, Janthinæ, Spirulæ;
often associated with _L. anatifera_ and _L. Hillii_, and, in a
young state, with _L. fascicularis_.
_General Appearance._--Capitulum more or less elongated relatively to
its breadth; in two specimens, with scuta of equal width, one was longer
than the other by the whole of the occludent margin of the terga. Valves
white, thick, (in young specimens sometimes diaphanous and thin,)
closely approximate to each other; surfaces furrowed to a very variable
amount. Terga generally more plainly furrowed than the scuta, of which
the basal portion is generally less furrowed than the upper part;
ridges, often rough, generally much narrower than the furrows: in
half-grown specimens (var., _dilatata_ of Leach,) the ridges are
frequently denticulated, and there is even sometimes a row of bead-like
teeth along the basal margins of the scuta. The ridges vary much,
sometimes alternately wide and narrow; in two specimens of equal size,
there were, in one, thirty-two ridges, and in the other only eighteen,
on the scutum.
_Scuta_, with the occludent margin rounded and protuberant to a variable
degree, but always leaving a rather wide space between the margin, and
the ridge which runs from the umbo to the apex; apex pointed. Right-hand
internal tooth considerably larger than that on the left, which is often
reduced to a mere ridge; internal basal rim thick, sometimes furrowed
along its upper edge, but of variable thickness, sometimes not extending
as far as the baso-carinal angle. _Terga_, sometimes equalling,
sometimes only two-thirds of, the length of the scuta; in young
specimens, the two occludent margins form a right-angle with each other;
in older specimens they form less than a right-angle, and hence the
portion of valve thus bounded is unusually protuberant. _Carina_, within
deeply concave; exterior sides finely furrowed longitudinally, generally
denticulated; valve only slightly narrowed in above the fork, of which
the prongs diverge at an angle of 90°, or rather more, and are wider
than the widest upper part of the valve; rim between the prongs
reflexed; the heel or external angle, just above the fork, sometimes
considerably prominent. I have seen only a single large specimen with
its carina barbed. In half-grown specimens, (var. _dilatata_, Leach,)
the carina is often strongly barbed, with the upper point much
acuminated, the fork about twice as wide as the widest upper part, and
the prongs diverging at rather more than a right-angle. In some
specimens, especially very young ones, there are at the base of the
carina, above the fork, some strong, downward-pointed, inwardly-hooked,
calcareous teeth; such occur also in some specimens along the basal
margins of the scuta, two of these hooked teeth under the umbones of the
scuta being larger than the rest: specimens conspicuously thus
characterised came from the Navigator Islands; in these, I may add, the
acutely triangular primordial valves were quite plain.
_Peduncle_, generally about as long as the capitulum; in young specimens
generally short.
_Filamentary Appendages_, generally five, sometimes six, on each side;
one is seated on the side of the prosoma, and the four others placed in
pairs beneath the basal articulation of the first cirrus; the lowest
posterior filament of the four generally is the largest. In young
specimens, having a capitulum only half an inch long, the upper pair of
the four often is not developed, or is represented by mere knobs. The
mouth presents no distinctive characters. _Cirri_, with the longer ramus
of the first pair almost equal to the shorter arms of the second pair;
spine-bearing surfaces only slightly protuberant. Caudal appendages
smooth, curved, pointed.
_Size._--The largest specimen which I have seen, had a capitulum one
inch and a half in length.
_Colours._--The white valves are edged with bright orange membrane; and
are so close to each other that no interspaces, coloured from the
underlying corium, are left. Peduncle, dark orange-brown, with the
uppermost part under the capitulum bright orange all round; the chitine
membrane itself being thus coloured. Sack, internally, dark purplish
lead-colour. Body and cirri, either nearly white or pale purplish-lead
colour, with the arms of the second, third, and fourth cirri, and
pedicels of the fifth and sixth, more or less tinted with orange. A
specimen preserved during fourteen months in good spirits had only a
tinge of orange left round the orifice and round the upper part of
peduncle, and on the cirri. In some other specimens, badly preserved,
the chitine membrane was quite colourless, and sack and cirri dirty
lead-colour. Fresh ova, peach-blossom-red; immature ova, in ovarian
tubes, pale pink.
_Monstrous Variety._--In Mr. Stutchbury’s collection, there was a
specimen, with the scuta, broad, smooth, thin, and fragile, without any
ridge running from the umbo to the apex, and with the occludent margin
reflexed. This seemed caused by the shell having been attacked by some
boring animal, and from having supported Balani. In the same specimen
the first cirrus on one side was monstrously thick and curled; the
second cirrus had its posterior ramus in a rudimentary condition. In Mr.
Cuming’s Collection, there are small specimens with the zones of growth
overlapping each other, with thick irregular margins, and with the
carina distorted.
This species has cost me much trouble: I have examined vast numbers of
specimens, from a tenth to half an inch in length, attached to light
floating objects, such as Janthinæ and Spirulæ from the tropical oceans,
which all resembled each other, and slightly differed from the common
appearance of _L. anserifera_: this variety is the _Pentalasmis
dilatata_ of Leach; and for a long time I considered it as a distinct
species. It differs from _L. anserifera_, in the less thickness of the
valves, in their being more finely and yet plainly furrowed; in the
greater width of the scuta; and more especially, of that part of the
valve lying between the occludent margin, and the ridge running from the
umbo to the apex; in the less elongation of the area in the terga,
bounded by the two occludent margins; and, lastly, in the less size of
the whole individual. The trophi and cirri are absolutely identical.
Lately, however, in carefully going over a great suite of specimens, all
the above few distinctive characters broke down and insensibly graduated
away; and I am convinced that this form is only a variety of _L.
anserifera_; its different aspect being caused partly by youth, but
chiefly, I suspect, from being attached to light objects floating close
to the surface of the sea.
The _Lepas anserifera_ can be distinguished by the slight furrows on its
valves from all the other species, excepting _L. pectinata_: this latter
species can be readily known, by the close proximity in the scuta of the
occludent margin, and the ridge extending from the umbo to the apex; by
its carina being very narrow above the fork; by the prongs of the fork
diverging at an angle of from 135° to 180°; by the thinness of its
valves; by the coarseness of the furrows on them; and lastly, by there
being at most in _L. pectinata_ only one filamentary appendage beneath
the first cirrus.
4. LEPAS PECTINATA. Pl. I, fig. 3.
LEPAS PECTINATA. _Spengler._ Skrifter Naturhist. Selbskabet, 2,
B. 2, H., 1793, Tab. X, fig. 2.
---- MURICATA (var.) _Poli._ Test. Utriusque Scicil., vol. i, Pl.
vi, figs. 23, 29, 1795.
LEPAS ANSERIFERA. _Poli._ Test. Utriusque Scicil., vol. i, Pl. vi,
figs. 25-27.
---- SULCATA. _Montagu._ Test. Brit., Pl. i, fig. 6, 1803.
PENTALASMIS SULCATA. _Leach._ Encyclop. Brit. Suppl., tom. iii,
Pl. lvii, 1824.
---- spirulæ (!) (var.) _Leach._ Tuckey’s Congo Expedit. Appendix,
1818.
---- RADULA (var.) et SULCATUS. _Brown._ Illust. of Conchology,
Pl. li, figs. 3-6, 1844.
---- INVERSUS. _Chenu._ Illust. Conchy., Pl. i, fig. 14.
ANATIFA SULCATA. _Quoy et Gaimard._ Voyage de l’Astrolabe, Pl.
xciii, figs. 18, 20.[28]
[28] I may add, that I have received many specimens incorrectly
labelled _A. striata_, which is properly a synonym of _L.
anserifera_.
_L. valvis tenuibus, crassè sulcatis, sæpe pectinatis; scutorum cristâ
prominente ab umbone ad apicem juxta marginem occludentem pertinente:
furcæ carinalis cruribus inter angulos 135° et 180° divergentibus._
Valves thin, coarsely furrowed, often pectinated. Scuta with a prominent
ridge extending, from the umbo to the apex, close to the occludent
margin; fork of the carina with the prongs diverging at an angle of from
135° to 180°.
Filaments absent, or only one on each side.
Var. (Pl. I, fig. 3 _a_), upper part of the terga (bounded by the two
occludent margins) produced and sharp; surface of all the valves often
coarsely pectinated, and with the carina barbed.
Atlantic Ocean, from the North of Ireland to off Cape Horn;
common, under the tropics; Mediterranean: attached to wood,
cork, charcoal, sea-weed, a reed-like leaf, spirulæ, cuttle-fish
bones, to a bottle together with _L. anatifera_; to a ship’s
bottom, Belfast, (W. Thompson.) Often associated with _L.
fascicularis_. Montagu states (‘Test. Brit.,’ p. 18) that this
species is sometimes attached to the fixed _Gorgonia flabellum_.
_General Appearance._--The capitulum varies considerably in length
compared to its breadth, caused chiefly by the greater or less
production of the occludent portion of the terga; valves thin, brittle;
the furrowed surface varies much in character, narrow and broad ridges
often alternating; frequently each ridge (but more especially the ridge
running from the umbo to the apex of each scutum, and sometimes that
alone,) is covered with prominent, curled, flat, calcareous spines,
giving the shell an appearance like that of many mollusca. Other
specimens show no trace of these calcified projections. From the
thinness of the valves and the depth of the furrows, the margins of the
valves are sinuous. _Scuta:_ the ridge running from the umbo to the apex
is unusually prominent and curved; it runs very close to the occludent
margin, so that, differently from in all the other species, only a very
narrow space is left between this margin and the ridge. Internal teeth,
under the umbones, either sharp and prominent, or mere knobs; sometimes
that on the right side is much larger than that on the left; sometimes
they are nearly equal; sometimes that on the left is scarcely
distinguishable. Internal basal rim absent, or barely developed.
_Terga:_ these valves have a conspicuous notch to receive the apex of
the scuta; the two occludent margins either meet each other at a
rectangle, or at a much smaller angle, causing the portion thus bounded
to vary much in outline, area, and degree of prominence. This at first
led me to think that the _P. spirulæ_ of Leach, in which the point is
very sharp and prominent, was a distinct species; but there are so many
intermediate forms, that the idea must be given up. I may remark, that
in all the species of Lepas, the upper part of the tergum seems
particularly variable. The degree of acumination of the basal portion of
the tergum also varies; the internal surface sometimes has small crests
radiating from the umbo.