LEPAS RADIATA. _Wood's_ General Conchology (1815), Pl. 7, fig. 7.
---- MINOR? _Wood's_ General Conchology (1815), Pl. 7, fig. 6.
---- BALANOIDES. _Poli._ Testacea utriusque Siciliæ (1795), Tab. 5.
BALANUS BALANOIDES. _Risso._ Hist. Nat. de l'Europe Merid., tom. iv,
1826.
_Shell longitudinally striped with purple or pink; sometimes with the
stripes confluent; sometimes wholly white. Scutum internally with a
prominent broad adductor ridge._
_Var._ (1) communis: (2 _e_, 2 _h_, 2 _l_,) _nearly white, with
pale or dark violet-coloured longitudinal stripes: epidermis rarely
persistent: shell either thin or thick: radii white or freckled
with reddish mahogany colour, with their summits either oblique,
sometimes in a high degree, or nearly parallel to the basis: basal
point of spur of the tergum either square or bluntly pointed_. Hab.
Mediterranean, W. Indies, S. Africa, Philippine Archipelago, New
South Wales.
_Var._ (2) venustus: (2 _a_,) _white or pale pink, with narrow bright
pink, or broad pinkish-purple stripes; orifice either much dentated
or nearly entire. Tergum with the carinal half of the basal margin
sometimes much hollowed out_. Hab. W. and S. Africa, Ceylon.
_Var._ (3) pallidus: (2 _c_, 2 _k_,) _white, with or without a
yellowish persistent epidermis; sometimes with the edges of the
compartments tinted purple: radii moderately oblique: tergum
generally narrow, with the spur sharp, and the basal margin on its
carinal side much hollowed out_. Hab. W. Africa, Madagascar, Red Sea.
_Var._ (4) niveus: (2 _f_,) _white, with longitudinal hyaline lines;
epidermis not persistent_. Hab. W. Indies, Florida, S. Africa, &c.
_Var._ (5) modestus: _upper part of shell white, lower part uniform
blueish-gray, opercular valves as in_ Var. (1). Hab. unknown.
_Var._ (6) Stutsburi: (2 _d_, 2 _i_, 2 _m_, 2 _n_, 2 _o_,) _white,
with or without pinkish-purple stripes, which are often confluent,
rendering the lower part of the shell of a uniform purplish tint;
epidermis persistent: radii very narrow: tergum narrow, spur sharp,
varying in form and in exact position; carinal margin sometimes
highly protuberant; basal margin on the carinal side of the spur
generally, but not invariably, much hollowed out_. Hab. West Africa.
_Var._ (7) obscurus: (Pl. 5, fig. 2 _g_,) _with narrow, approximate,
obscure and often almost confluent, slaty, or pale purplish-brown,
or dark slate-coloured stripes_. Hab. West Indies, Australia, and
unknown.
_Var._ (8) variegatus: _with narrow, approximate, dusky,
claret-coloured stripes, transversely freckled with white; shell
conical; walls very thin: scutum with the adductor ridge small_. Hab.
New Zealand.
_Var._ (9) (_an. spec._?) cirratus: (fig. 2 _b_,) _shell very pale
purplish-brown, with faint, more or less plain longitudinal stripes,
transversely freckled with white; walls thin: scuta with the lines of
growth beaded: basis, in specimens growing in groups, irregularly cup
formed: maxillæ with the inferior corner extremely prominent_. Hab.
Mouth of Indus, Australia, Philippine Archipelago.
_Hab._--Warmer temperate and tropical seas; extremely common;
Mediterranean, Smyrna, Sicily, Coast of Portugal; West Coast of
Africa, River Gambia, West Indies, Demerara, Natal, Madagascar, Red
Sea, Mouth of the Indus, Ceylon, Philippine Archipelago, East Indian
Archipelago, Pacific Ocean, east coast of Australia, New Zealand;
extremely common on ships' bottoms; often attached to floating
timber, canes, &c.; often associated with _B. tintinnabulum_;
attached to pebbles and various shells.
With respect to the nomenclature of this extremely common species,
which is widely distributed in all the warmer seas (excepting, as
far as I have seen, on the west coast of America), there is some
difficulty. I have no doubt that it is the _Lepas radiata_ of Wood
(1815), but Bruguière, in 1789, gave this same name to a Balanus which
he had not seen, but which is figured in Chemnitz, Tab. 59, fig. 842.
I should have thought that this also had been the present species,
but Spengler, in describing (Skrifter af Naturhist. Selskabet i, B.
1790) this individual specimen, which he calls _L. purpurea_, states
that it is 13 lines in basal diameter; now this is a size which is
never acquired by _B. amphitrite_; and the description, habits, and
size, would apply equally well to the species which I have called _B.
amaryllis_; but when no notice is taken of such points of importance,
as whether the walls are permeated by pores, whether the radii are
smooth-edged, whether the scuta are striated, it is impossible to
identify with any approach to certainty sessile Cirripedes; and
the names given ought, in my opinion, to carry little weight with
them. With respect to Lamarck's _Balanus radiatus_ (1818), the
synonyms quoted exhibit some great and inextricable confusion. The
_B. radiatus_, again, of Risso, is a fossil and apparently distinct
species. There can be no doubt that the present species is the _Lepas
balanoides_ of Poli, (and of several authors who have followed him),
and equally little doubt that the present species is not the true _L.
balanoides_ of Linnæus, which has a membranous basis, and which I have
not seen from the Mediterranean. Under these circumstances I have
concluded that less confusion would be caused by giving a new name to
this species than by taking that of Wood, which ought not to have been
used by him, considering Bruguière's previous adoption of it.
Under the head of _B. tintinnabulum_ I have alluded to the great
variation of _B. amphitrite_, which consists not only in a vast
diversity in the colouring and in the general aspect, but likewise
in the degree of obliquity of the summits of the radii, in the form
of the terga, and slightly in that of the scuta. In order to show
that it has not been from indolence that I have put so many forms
together, I may state that I had already named and fully described
in detail eight of the following forms as species, when I became
finally convinced that they were only varieties: it would require at
least thirty figures, which I have not the power to give, fully to
illustrate the transitional forms. As with _B. tintinnabulum_, the
deception is wonderfully enhanced by whole groups of specimens from the
same locality exactly resembling each other, and sometimes differing
from other groups attached to the very same object. If a person were
to get together only some fifty or sixty specimens from only half a
dozen different localities, he would almost certainly come to the same
conclusion, as I at first did, that several of the varieties are true
species; but when he gets several hundred specimens from all quarters
of the globe, he will find, to his trouble and vexation, that character
after character fails and blends away by insensible degrees, and he
will be led, as the more prudent course, to include, as I have done,
and I hope rightly, all under one specific name. I have experienced
more doubt regarding the last variety, _cirratus_, than on any other,
on account of its peculiar colouring, and from the basis being often
irregularly cup-formed. Under _B. concavus_ I have remarked how closely
some of its varieties approach to _B. amphitrite_, and it is to this
last variety that they approach; almost the only difference being that
the scuta in _B. concavus_ are longitudinally striated. Yet some of the
varieties of the two species are so distinct that it would be puerile
to class them together. I will only add, that after studying such
varying forms as _B. tintinnabulum_ and _amphitrite_ it is difficult to
avoid, in utter despair, doubting whether there be such a thing as a
distinct species, or at least more than half a dozen distinct species,
in the whole genus Balanus.
As with _B. tintinnabulum_, I will first give a full description of the
more common forms, alluding only to each less frequent variation, and
then separately describe briefly the more marked varieties.
_General Appearance._--Shape conical, either steep or considerably
depressed; sometimes tubular; orifice either nearly entire or deeply
toothed, not large, varying from rhomboidal to rounded-trigonal.
Surface of shell smooth, never ribbed, generally naked, but
occasionally the yellowish epidermis is persistent; in the same
individual, I have seen all the lower part of the shell thus covered
and the upper part naked, the line of separation being defined.
The _colour_ varies much, even sometimes considerably on the same
individual; generally white or pale gray, with dull violet-coloured,
longitudinal, moderately broad stripes; these stripes are sometimes
equidistant, but more usually they are arranged so as to leave
broad white spaces; the stripes fade away by endless variations,
the edges of the compartments and the carinal end of the shell
longest retaining any colour, until we have a uniformly white
shell, generally covered with a yellowish epidermis; or the white
is longitudinally marked with hyaline lines; this latter variety
has a very peculiar aspect, and I did not doubt it was specifically
distinct, until, in a number of specimens on a ship from the West
Indies, I got the most perfect series, and another scarcely less
perfect series from the Mediterranean, graduating into common
coloured varieties. Rarely the dull violet or purple stripes become
approximate and dark, so that the whole shell is tinted of a brownish
slate-colour, occasionally freckled with white. Again, we have
another set of very pretty varieties, with a white or very pale
pink ground, with either narrow bright pink or broad pinkish-purple
stripes. Again, I have seen numerous specimens of a variety, _var.
Stutsburi_, from the west coast of Africa, in which the upper part
of the shell is white, and the lower part shaded with pinkish or
dark purple approximate stripes, which often become confluent; in
one group, the whole shell being thus uniformly coloured, without
any vestige of stripes. I have seen another group from an unknown
locality, in which the lower part of the shell was uniformly
blueish-gray. A variety from Australia has narrow approximate dark
claret-coloured stripes, transversely freckled with white. Lastly, in
the variety _cirratus_, the whole shell is very pale purplish-brown,
with indistinct longitudinal brownish stripes, transversely freckled
with white lines. I considered this as a distinct species, until
quite lately finding forms which I could not possibly determine
whether to class as _B. cirratus_ or _amphitrite_.
The radii are generally snow-white, or freckled with a bright
mahogany tint, or rarely clouded with purple, or in the pink
varieties with pink. The scuta are dull purple or pink, generally
with a white band along their tergal margin; often, however, they
are white, with merely one or two purple fasciæ. The thickness or
strength of the shells varies much; some specimens attached to a
floating cane, from Natal and the Philippine Archipelago, were
extremely strong; others, from the Mediterranean and Australia,
and some tubular varieties from the West Indies, were very thin,
translucent, and fragile. _Size_: large specimens generally attain a
diameter of from half to three quarters of an inch in basal diameter;
and I have seen one or two specimens an inch in diameter.
_Scutum_; sometimes the surface is very smooth, but generally the
growth-ridges are moderately prominent; the latter are occasionally
very finely beaded, and this seems always the case with _var.
cirratus_. Internally, the articular ridge is prominent and reflexed:
the adductor ridge is sharp, very prominent, and straight; it runs
parallel to the occludent margin; close to its lower side there is
often a depression (Pl. 5, fig. 2 _i_), sometimes bounded by a slight
ridge, as if for the attachment of a muscle, but there certainly is
no muscle here: rarely the adductor ridge is only slightly prominent:
there is a small and shallow little pit of variable depth for the
lateral depressor muscle.
_Tergum_ (2 _k_-2 _o_); this valve is here far more variable than in
any other species: in the commonest purple-striped forms (2 _l_), the
valve is rather broad, the basal margin lies in nearly a straight
line on the opposite sides of the spur, which is placed at rather
less than its own width from the basi-scutal angle; the spur is
rather short, and in width about one fourth of the entire valve; its
lower end is either bluntly pointed or more commonly nearly square
(2 _k_) and parallel to the basal margin: in young specimens it is
generally sharper than in older ones. Externally, in the line of
the spur, there is either a slight longitudinal depression, or more
rarely a deep furrow. The carinal margin is more or less convex, and
is formed by upturned lines of growth: the scutal margin is broadly
inflected. Internally, the articular ridge in the upper part is very
prominent: the crests for the tergal depressor muscle are moderately
prominent, but very variable. Sometimes the carinal portion of the
basal margin is slightly hollowed out. In _var. Stutsburi_ (2 _m_, 2
_n_, 2 _o_), and in some white varieties, which differ most in the
shape of the tergum from the commoner varieties, the whole valve is
narrower, the spur is much sharper and narrower, the carinal half of
the basal margin is much hollowed out and slopes down towards the
spur, with the crests for the depressor muscles depending beneath the
basal margin, and with the carinal margin sometimes extremely convex
or protuberant. But the shape and position of the spur, and the
outline of the carinal half of the basal margin vary much in nearly
all the varieties.
_Compartments._--The upper parts of the parietal pores are either
filled up solidly with, generally coloured, shell, or they are
crossed by thin transverse calcerous septa: the longitudinal parietal
septa occasionally bifurcate at their bases close to the outer
lamina, making an irregular outer row of minute pores. The _Radii_
have their septa rather fine, and finely denticulated on both sides,
but sometimes only on the lower side; the thickness of the septa
varies a little; the interspaces are filled up solidly; the summits
of the radii are jagged and oblique, and usually form an angle of
about 45° with the basis, not being added to above the level of the
opercular membrane; but not rarely they reach up much higher, and
are very nearly parallel to the basis, extending from tip to tip of
the compartments. Again, in some ordinary varieties, and always in
_var. Stutsburi_, the summits of the radii are extremely oblique, the
radii themselves forming a mere border to the compartments to which
they belong. In no other species have I seen so great an amount of
variation in the form of the summits of the radii. The _alæ_, in like
manner, have their summits either very oblique, not being added to
above the opercular membrane, or they are only slightly oblique; it
often happens that in those specimens in which the summits of the
radii are nearly parallel to the basis, the alæ are very oblique, and
the converse: in other individuals, both radii and alæ have equally
oblique summits. The sutural edges of the alæ vary in thickness,
being either very thin and obscurely crenated, or moderately
thick and ribbed. The _basis_ is porose; but I have never seen an
underlying cancellated layer of shell, as is so common in several
species.
_Mouth_: labrum, with from four to eight, generally with six, little
teeth: mandibles with three teeth, and two minute lower teeth, or
mere knobs: maxillæ with the edge straight, or with the inferior
part forming a slightly step-formed projection. _Cirri_: the rami
of the first pair are unequal by three or four segments, but in
some specimens by five or six segments, with the front surfaces of
the segments in the shorter ramus extremely protuberant. The second
pair of cirri are short, with the front surfaces of the segments
moderately protuberant: the third pair have a tuft of bristles at
their bases on the thorax. The segments in the sixth pair have from
four to six pairs of spines on the segments; equal-sized specimens
seem to vary in this latter respect. There is a small sharp
projection on the dorsal base of the penis.
_Varieties._
With respect to _var._ 1, _communis_, I have nothing further to
remark, except that I have seen specimens identically similar from
the Mediterranean, Natal, the Philippine Archipelago, and Sydney;
at the latter place it is said to be rare, but in most places it is
the commonest variety, and is often attached to ships' bottoms. Of
_var._ 2, _venustus_, I have seen specimens from the west coast of
Africa, Natal, and Ceylon, in groups by themselves, and associated
with _var. communis_; it is much less common than _var._ 1. The third
variety, _pallidus_, is not uncommon; I have seen many specimens
from the bottoms of ships, from the West Indies, and the west coast
of Africa. Of the _var._ 4, _niveus_, I have seen the most perfect
graduated series passing into _var._ 1, both from the West Indies,
Florida, and the Mediterranean: I have seen other specimens from the
Red Sea and Madagascar. Of the _var._ 5, _modestus_, I have seen
only one group from an unknown locality; it is only remarkable from
its uniform colouring. The _var._ 6, _Stutsburi_, is more remarkable
than the foregoing; until quite lately I did not doubt that it was
specifically distinct; but as I have seen every character graduate
into other varieties, I am now convinced that it is not a true
species: all the specimens which I have seen have come on shells,
or on ships' bottoms, from West Africa. Of _var._ 7, _obscurus_, I
have seen three or four groups of specimens from unknown quarters,
both on pebbles, shells, and on cork (probably from the Atlantic
ocean); and likewise some specimens taken from the bottom of Her
Majesty's ship "Fly," on the east coast of Australia; these latter
are intermediate in character with the next _var. variegatus_;
from the Australian seas, which I at first ranked as an undoubted
species, but I have subsequently failed in discovering any sufficient
diagnostic character. Lastly, of _var. cirratus_, I have seen several
groups of specimens from India and the Philippine Archipelago, and
a group intermediate in character between this and the first and
third varieties, from Australia; I retained this variety owing to
its peculiar freckled, pale brown colouring and beaded scuta (of
which, however, I have seen decided traces in the common variety),
as a distinct species, after I had given up all the foregoing forms.
I entertain some doubts whether I have now acted right; but when I
found some specimens which, I found it impossible to decide, whether
to rank as _amphitrite_ or _cirratus_, I determined to take the more
prudent course, and sink the latter as a species. This variety, also,
seems to connect _B. amphitrite_ and _concavus_ very closely.