Chapter XVII: Introduction (13)

_Mouth_: labrum with six teeth: mandibles with the fourth tooth
minute or rudimentary, and the fifth generally confluent with the
inferior angle. Maxillæ with generally, but not invariably, a small
notch under the upper pair of great spines. _Cirri_, first pair with
the rami very unequal in length, one ramus being nearly twice the
length of the other; in a large specimen having a cylindrical shell
the proportional numbers of the segments in the two rami of the first
cirrus were ten to twenty-three; in a small conical specimen the
numbers were only eight to thirteen. The second cirrus has only two
or three more segments than the shorter ramus of the first pair: the
third cirrus has one or two more segments than the second; but it is
nevertheless decidedly longer than the second. On the dorsal surfaces
of both segments of the pedicel of the third cirrus, there is a
tuft of fine spines. The segments of these three pairs of cirri are
not much protuberant in front. The segments of the posterior cirri
have, each, four, or five, or six pairs of spines. _Penis_, with a
straight, sharp, short point on the dorsal basis.

_Range, habits, &c._--I have received specimens from all parts of the
coast of Great Britain and Ireland, generally attached to crustacea
and mollusca, and never hitherto from rocks uncovered by the tide.
This species is also attached to floating timber, sticks, fuci, and
occasionally to pebbles at the bottom of the sea. Mr. Thompson has
sent me specimens from twenty-five fathoms depth in Belfast Bay:
others on a Pinna from _about_ fifty fathoms on the coast of Antrim;
others from between three and six fathoms attached to Laminaria
digitata: there is a specimen in Mr. Jeffreys' collection marked
forty-five fathoms. It is often associated, both on the coasts of
America and Britain, with _B. porcatus_, and though these species are
so distinct, yet when both have their surfaces similarly affected by
being attached, as is often the case, to large Pectens, it is not at
first easy, by external characters, to distinguish them, except by
close inspection of the terga, which in _B. porcatus_ are beaked and
purple. The _B. crenatus_ is sometimes associated in deep water with
_B. Hameri_. At Ramsgate, in Kent, I saw a rudder of a ship, in which
the two or three upper feet were thickly coated with _B. balanoides_,
and the two or three lower feet with _B. crenatus_ and _improvisus_
mingled, together with a few of _B. balanoides_: occasionally
vessels are thickly encrusted with this species, but I have never
seen an instance of its concurrence with _B. tintinnabulum_ and
_amphitrite_--the commonest species on ships coming from the south.
I have seen specimens from Greenland, Baffin's Bay, the coast of
Labrador, and other specimens marked simply, "Arctic regions," and,
again, others from the shores of Maine and Massachussetts. The arctic
specimens, and those from the northern United States, are larger
than the British. I have seen one single minute specimen on a crab,
marked as having come from the Mediterranean. In the British Museum,
amongst some specimens of _B. eburneus_, ticketed as having been sent
from Jamaica, there was a small group of specimens, differing in no
one essential respect from the common varieties of _B. crenatus_:
at first I concluded that this was an erroneous habitat, and that
the specimens had really come from the United States, where _B.
eburneus_, is found as well as in the West Indies: for it appeared
to me exceedingly improbable that an animal which can exist in lat.
75° N. should inhabit the hot shores of Jamaica: but subsequently I
have received a specimen from Prof. Krauss, collected by himself in
Algoa Bay, which is perfectly characterised, and even has the little
cells in the furrow under the sheath: so that I am compelled to admit
this enormous range and capability of resisting the most extreme
climates. That this species should live in the tropical seas is the
more surprising, as the large size of the specimens in the northern
seas and in the glacial deposits, might fairly have been supposed
to have indicated special adaptation for a cold climate. The great
geographical range of this species accords with its range in time
from the present day to the Coralline Crag period.

The specimens from the glacial deposits which I have examined,
chiefly in Sir C. Lyell's collection, are very fine and large; they
are often associated, like the now living individuals, with _B.
porcatus_ and _Hameri_: they come from the well-known formation of
Uddevalla and from Canada. There are well-characterised specimens
in the mammaliferous Crag, at Bramerton and near Norwich, in Sir C.
Lyell's collection, and from Sutton and other places in the Red Crag
of the eastern shores of England: these specimens are decidedly not
only smaller than the glacial, but than the recent English specimens;
for the largest Crag specimens which I have seen had a basal diameter
of only .35 of an inch. The specimens which I have seen from the
Coralline Crag, and some others sent me by Krantz from the miocene
formation of Flonheim bei Abzei, in Germany, had not their opercular
valves, yet I cannot doubt, considering how few species there are in
the present section of the genus, that I have rightly identified them.

_Diagnosis._--Under the head of _B. balanoides_ I shall make a few
remarks on the diagnosis between that and the present species; as _B.
improvisus_ is found on the British shores, sometimes mingled with
_B. crenatus_, I may observe that, externally, the only difference
consists in the edges of the radii in _B. improvisus_ being much
smoother and rounded, and in the whole shell being less rugged.
Internally, in _B. improvisus_ the porose basis, the presence of an
adductor ridge on the under side of the scutum, the graduated teeth
on each side of the central notch in the labrum, and the little
inequality in length of the rami of the first pair of cirri, are
clearly and amply diagnostic.

28. BALANUS GLANDULA. Pl. 7, fig. 1 _a_, 1 _b_.

_Shell white; parietes with the internal lamina generally strongly ribbed longitudinally, with the pores imperfect and small, sometimes in part absent; radii narrow, with their summits rounded. Scutum with an adductor ridge; tergum with the spur truncated and rounded._

_Habitat._--California, Mus. Cuming, Aug. Gould; attached to shells
and wood, together with _B. nubilus_. Southern Pacific ocean,
attached to _Pollicipes polymerus_; Mus. Brit.

_General Appearance._--Shell steeply conical, or cylindrical and
elongated; dirty white; walls rugged, longitudinally folded; radii
narrow, with their summits very oblique and rounded; orifice toothed.
Basal diameter of largest specimen half an inch.

_Scutum_, resembling externally that of _B. crenatus_; rather broad,
surface smooth; articular ridge very prominent, and articular furrow
very wide; hence, when the summits of the opercular valves are worn
down, the two scuta together form a square projection indenting
the two terga, as in _B. balanoides_. Internally, there is a small
adductor ridge, on the lower side of which there is a pit, as if
for a muscle. The depression for the lateral depressor muscle is
small, but variable. _Tergum_ without any longitudinal furrow, and
hardly a depression: spur broad, with its lower end truncated and
rounded; internally, articular ridge very prominent; crests for the
depressores well developed.

_Compartments_:--The internal surface of the parietes is smooth in
the upper part beneath the sheath, but generally very strongly ribbed
in the lower part, the ribs being plainly denticulated at their
bases; in other specimens, the ribs are very small, and even in parts
quite obsolete. The parietal pores are short and imperfect, sometimes
reduced to an extremely minute size, to be detected only when the
walls are broken across near the basal edge, and most carefully
examined; occasionally not even a trace of a pore exists. Hence in
this respect, this species offers a singular case of variation. The
_radii_ are narrow, and of nearly the same width from top to bottom;
their very oblique summits, when well preserved, are smooth and
rounded; their sutural edges are ribbed or crenated with extremely
fine, smooth septa; the recipient furrow is plainly marked by these
septa. The sutural edges of the alæ are crenated; their summits are
less oblique than those of the radii.

_Basis_, thin, finely furrowed in lines radiating from the centre;
margin sometimes deeply sinuous.

_Mouth_: labrum with the central notch rather widely open, with four
teeth on each side of it: palpi with very short spines along their
inner margins: mandibles with the fourth and fifth teeth forming
mere knobs: maxillæ small, with a mere trace of a notch under the
two great upper spines. _Cirri_; first pair with the rami unequal by
three or four segments, the longer ramus being only one quarter of
its own length longer than the other ramus. Second pair short, with
the segments (and those of the shorter ramus of first pair) somewhat
protuberant. Third pair with the rami one third longer than those of
the second pair. Sixth pair with the upper segments elongated, and
bearing six or seven pairs of spines.

_Affinities._--This species in general appearance closely approaches
_B. crenatus_ and _balanoides_, and it is related to them in many
essential parts, such as in the opercular valves. It agrees with _B.
balanoides_, and differs from _B. crenatus_, in the smallness and
imperfection of the parietal pores, and in the radii having rounded
summits; it agrees with _B. crenatus_ in the structure of its basis,
and in the prominent longitudinal ribs on the internal surface of the
parietes, and differs from that species in the spur of the tergum
being squarer, and in the scutum having an adductor ridge.

_Range._--From the appearance of the Californian specimens, I suspect
that they had adhered to tidal shells and to wood. The specimens in
the British Museum, adhering to _Pollicipes polymerus_, consist of
two lots, one of unknown origin, and the other certainly brought from
the southern half of the Pacific Ocean by Sir James Ross: it deserves
notice, that the _Pollicipes polymerus_, the supporting object,
ranges from California to the southern Pacific Ocean.

_Section_ E.

_Basis membranous._

29. BALANUS BALANOIDES. Pl. 7, fig. 2 _a_-2 _d_.

LEPAS BALANOIDES. _Linn._ Fauna Succica, 1746, et Syst. Naturæ, 1767.

---- ---- _O. Fabricius._ Fauna Groen., p. 424, 1780.

---- ---- ET CLIVATUS. _Montagu_ (!). Test. Brit., 1803.

BALANUS VULGARIS (?) _Da Costa._ Hist. Nat. Testacea, Pl. 17, fig. 7,
1778.

---- OVULARIS ET ELONGATUS. _Aug. Gould_ (!). Report, Invertebrata
of Massachussetts, figs. 7 and 8, (1841).

---- PUNCTATUS, CYLINDRICUS, ELONGATUS, FISTULOSUS CLAVATUS.
_Auctorum variorum_. Sed non B. punctatus, _Bruguière_,
Encyclop. Method., et non B. punctatus, _Montagu_, Test. Brit.

_Parietes either solid, or cancellated, or rarely formed by a single row of pores. Tergum, with the spur bluntly or sharply pointed._

_Var._ (_a_) _with the parietes permeated by tubes; spur of tergum
sharply pointed; segments in the posterior pairs of cirri, bearing
from eight to ten pairs of spines_.

_Habitat._--Great Britain, France, Norway, Shetland Islands;
Greenland, according to O. Fabricius; North America, in lat. 66°
34′ N.; Labrador; Nova Scotia; Massachussetts, Delaware. Extremely
common, attached to rocks, shells, and wood, within the tidal limits.

I have no doubt that the present species is the _Lepas balanoides_ of Linnæus; though O. Fabricius is the only author who gives, in his "Fauna Groenlandica," a sufficient description for the species to be recognised with certainty. I believe this also is the _B. balanoides_ of Bruguière, though he is in error, as far as my experience goes, in stating that the basis is ever calcareous. I have little doubt, also, that this is the _B. vulgaris_ of Da Costa. The _B. balanoides_, in its corroded and therefore punctured state, is certainly the _B. punctatus_ of most British collections; but I do not believe it is the _B. punctatus_ of Montagu, which I have scarcely any doubt is the _Chthamalus stellatus_, so often found in the southern shores of England, and even in some of the best arranged collections, mingled with our present species.

_General Appearance._--The shell, in middle-sized and old specimens,
is almost invariably folded longitudinally and irregularly; it is
either dirty white or very often pale brown, and punctured from the
outer lamina having been corroded, to which action it is extremely
subject. In very young specimens, the surface is usually quite white
and smooth. The shell is sometimes much depressed; generally conical,
but when crowded together, cylindrical or club-shaped, one specimen
being even more than five-and-a-half times as long as wide. In Mr.
Jeffreys' collection there is a specimen 2.5 of an inch long, .45 in
diameter at the summit, only .2 in the middle, and rather more than
.2 near the base. Another specimen was 1.8 in length, its greatest
diameter being .35 of an inch at the summit. On the other hand, I
have seen a very depressed variety, with deeply folded walls, in
Mr. Thompson's collection from near Dublin, which was no less than
four times as wide as high; so that the difference in proportion of
height and greatest width, in the two extreme specimens, was nearly
as 10 to 1. Occasionally, from some unknown cause, isolated specimens
become cylindrical. The orifice of the shell, in the much elongated
specimens, is generally deeply toothed. The radii are always narrow,
sometimes extremely narrow, and have their summits smooth and rounded.

English specimens do not usually attain half an inch in basal
diameter; I have, however, seen one from near Yarmouth .9 of an inch
in diameter. Specimens from Massachussetts seem rather larger than
the average size of British specimens, many being .6 of an inch, and
one specimen a whole inch in basal diameter.

The _opercular_ valves so closely resemble those of _B. crenatus_,
that the description is necessarily comparative; in some cases they
could hardly be discriminated; generally, owing to the disintegration
to which this species is subject, the tips of the scuta are worn off,
and hence the articular ridges together form (Pl. 7, fig. 2 _a_) a
square projection, indenting the two terga; but I have examined young
specimens and others when not disintegrated, in which the opercular
valves, viewed externally, presented no difference whatever from
those of _B. crenatus_. The _scuta_, however, are, I think, generally
rather thicker, with the growth-ridges more prominent, and with
the tips certainly less reflexed than is usual with _B. crenatus_.
Internally, the articular ridge is rather less prominent: there is
no distinct adductor ridge. The _terga_ are often rather narrower
in proportion, and this especially holds good in the elongated
varieties; in these latter, there is occasionally a moderately deep
longitudinal furrow: the spur is often exactly the same shape as in
_B. crenatus_, but it is apt to be rather longer (Pl. 7, fig. 2 _c_)
and more pointed: in _var._ (_a_) it is pointed (fig. 2 _d_) in a
very remarkable manner. Internally, the articular ridge is decidedly
more prominent than in _B. crenatus_; the crests for the tergal
depressor muscles are either well developed or almost absent. From
this description it will be seen, how singularly the opercular valves
of the common varieties of these two species resemble each other. I
may mention that in some of the much elongated specimens, the muscles
going to the opercular valves partially lose their transverse striæ,
and become ligamentous.

The _Parietes_ are either quite solid, or more commonly are permeated
by minute pores, or by small irregular square tubes (Pl. 7, fig. 2
_b_), which only run up each successive zone of growth, for very
short distances, giving to the shell a cancellated structure, which
from corrosion is often externally visible. In the rather rare
variety (_a_) the parietes are permeated by regular tubes, extending
up to the apices of the compartments, but crossed by transverse
septa. The longitudinal septa, when such can be said to occur, in
no case are denticulated at their bases. The internal surface of
the parietes is either quite smooth or is traversed (Pl. 7, fig. 2
_b_) by very slight anastomosing ridges, but never, even in _var._
(_a_), by regular longitudinal ribs, as in most other species. The
carinal margin of each compartment, on the inside, projects, as in
_B. crenatus_, inwards, beyond the general surface of the shell, and
running down, rests on the basal membrane. The lower edge of the
sheath is rarely hollow beneath. The walls are lined by purplish,
or pale brown, or sometimes by almost black corium; numerous tubuli
penetrate the under sides of the walls and opercular valves; and
it is the intersection of these tubuli that gives the punctured
appearance to the often corroded surface of the shell. The _radii_
are narrow, generally very narrow; they have their upper and outer
margins, as seen externally, very oblique, rounded and (when well
preserved) smooth; their sutural edges are either quite smooth,
or sometimes just perceptibly pitted, like the basal margin of
the walls, or occasionally furnished with globular or arborescent
little ridges. The _alæ_ are also very oblique, but to a variable
degree, sometimes only slightly oblique: their sutural edges are
either smooth or obscurely crenated. _Basis_, membranous; in some
much elongated specimens, during continued growth, the basal edges
of the compartments approach each other so closely as almost to
touch, so that the whole shell becomes pointed at the bottom; but
on careful inspection I have never failed to find, even in the most
pointed specimens, a minute basal membrane; in other much elongated
varieties, in which the shell has apparently become too large for the
animal's body, the basal membrane, instead of being flat, becomes
drawn up deeply inwards, so as to touch the surface of attachment
only close round the basal edges of the shell.

_Mouth_: labrum with the teeth on each side of the central notch
unusually variable in number; I have seen specimens with only two
on each side, with four on each side, with five on one side and
four on the other, with five on one side and none on the other,
and with six on both sides; hence the total number ranges from four
to twelve. Mandibles, with the fourth and fifth teeth small, or
quite rudimentary. Maxillæ, with scarcely even a trace of a notch
under the upper pair of spines. _Cirri_; first pair, with one ramus
one third or one fourth longer than the other; in one specimen the
number of segments were nine and sixteen in the two rami: second
and third cirri short, very nearly equal in length, having in the
just-mentioned specimen respectively ten and eleven segments; the
sixth cirrus in this same specimen had twenty-five segments, each
segment being about as long as broad, and supporting six pairs of
spines. In the singular variety (_a_) the posterior cirri are more
elongated, and each segment supports seven or eight, and in one case
even ten pairs of spines! the third pair is also in this variety
proportionally rather longer. At the base of the third pair there
is a tuft of fine spines. The penis has not, as in _B. crenatus_, a
point at its dorsal basis. The branchiæ are very little plicated.

_Varieties._

Of the varieties having much elongated, club-shaped, hour-glass
shaped, and depressed shells, there is no necessity to say anything
in particular. With respect to the remarkable variety (_a_), I at
first named and described it as a distinct species: I have received
two lots, both from North America, one being sent me by Professor
Agassiz from Cape Cod. These agreed in having the parietes permeated
by regular tubes; in having the spur of the tergum most sharply
pointed; in the third pair of cirri being proportionally longer
compared with the second pair; in the sixth pair having more numerous
segments, namely, three times as many as in the third pair; in the
segments of the posterior cirri being more elongated, and especially
in the number of pairs of spines on each segment--amounting in one
case even to ten, a number unparalleled in other cirripedes. It may
naturally be asked why I have not retained so well marked a form as
a distinct species? In the first place, I found the most remarkable
character in _var._ (_a_), namely, the number of pairs of spines
on the posterior cirri variable, there being in one lot seven or
eight pairs, and in the other lot nine or ten pairs on each segment.
Secondly, all the characters by which this variety differs from the
common _B. balanoides_, are those which are variable in the latter;
this is especially the case with the structure of the parietes, and
in a lesser degree with the spur of the tergum. Thirdly, I found a
specimen in Mr. Cuming's collection, from Sweden (so that this _var._
(_a_) is not confined to North America), in which the cirri quite
resembled those of the American specimens, but the spur of the tergum
was in an intermediate condition as compared to that of ordinary
varieties; and the parietal tubes were of unequal sizes, and scarcely
more regular than sometimes in the true _B. balanoides_. And lastly,
I have seen specimens from Ayrshire, with the parietes permeated by
regular tubes, but with the tergum in an intermediate condition, and
with the segments of the posterior cirri not more numerous or more
elongated than in _B. balanoides_, supporting only six or seven pairs
of spines, that is only one more than is common with _B. balanoides_;
so that it was impossible to decide whether to rank the Ayrshire
specimen under _var._ (_a_) or under the common form, so that I was
compelled to give up _var._ (_a_) as a species.

_Monstrous individuals, with the male organs aborted:
Parasite._--Amongst some specimens, chiefly elongated ones, sent to
me from Tenby, in South Wales, I found no less than seven individuals
with some of the posterior cirri distorted, unequal on the opposite
sides, and in an almost rudimentary condition, and in each case
with the penis truncated, without any muscle entering the stump,
which was _absolutely imperforate_: the vesiculæ seminales were
much shrunk; in one case without any zoosperms; in another case
with headless zoosperms cohering in an unusual manner; hence it is
certain that these individuals were functionally only female, and
could not impregnate their own ova; yet in two instances the ova
had been impregnated, no doubt by neighbouring perfect individuals,
for they contained well-developed larvæ. Several of these monstrous
individuals were infested by one, two, or three curious crustaceans,
which have been described by Mr. Goodsir,[97] as the male of the
Balanus; but these supposed males are females, and were distended
with ova containing almost mature larvæ; I believe that they are the
females of the unnamed genus, belonging to the family of Ioniens,
described by Mr. Goodsir, which live parasitic within the sack (as I
likewise found) of the same individual Balani.

[97] 'Edinburgh New Philosophical Journal,' July, 1843.

_Diagnosis._--I have seen several specimens of this species and of
_B. crenatus_, absolutely undistinguishable in external appearance. I
may specify one of _B. balanoides_, imbedded in an alcyonidium, and
one of _B. crenatus_, imbedded in a sponge, and therefore neither at
all abraded. Generally, the tips of the scuta in _B. crenatus_ are a
little reflexed, whereas in _B. balanoides_, when the shell has been
at all disintegrated, the tips form a square projection locked into
the terga. _Bal. crenatus_ never assumes the punctured appearance so
common in _B. balanoides_. Very young specimens of the latter can be
distinguished by their dead white colour and smoothness. The edges
of the radii are almost always smoother than in _B. crenatus_, and
they are never so wide as is sometimes the case with _B. crenatus_.
When a specimen is disarticulated, our present species can at once
be distinguished from _B. crenatus_ (and from _B. improvisus_), by
its membranous basis, and by the solid or cancellated walls, which
are rarely permeated by regular tubes or pores; and the walls when
porose are not internally ribbed. I have already pointed out the
few very trifling points, in which the opercula of the two species
differ. The mouth and cirri offer likewise very few differences: in
_B. balanoides_ there are often more teeth on the labrum than in _B.
crenatus_; the rami of the first cirri are perhaps here rather less
unequal; the second and third pairs of cirri are certainly in most
cases more equal in length; and lastly, the segments of the sixth
cirri, even in the common varieties, bear, in equal-sized specimens,
more pairs of spines than in _B. crenatus_. We shall see that in
habits, with regard to depth, the two species differ, _B. balanoides_
inhabiting much shallower water than _B. crenatus_.

_Range, Habitats, &c._--This species is extraordinarily abundant
within the tidal limits round the shores of Great Britain, and
apparently of the northern United States. Besides numerous specimens
sent to me from very many English localities, the late Mr. W.
Thompson, of Belfast, kindly placed in my hands his very large
collection; from these materials it appears that _B. balanoides_
is the only tidal species in the northern parts of our island; but
in the south and south-west, it is associated with the _Chthamalus
stellatus_ and _Balanus perforatus_. I doubt whether this species
ever lives below the lowest tides; the case of a few specimens being
mingled with _B. improvisus_ and _crenatus_, (mentioned under the
latter species,) at the bottom of a rudder of a small vessel, about
six feet deep, is hardly an exception, for the water would there
be troubled and aërated almost as in a breaker; and on this very
rudder the upper two or three feet were coated exclusively by the
_B. balanoides_. This species lives on rocks at both the uppermost
and lowest limit of the tides; I am informed by Mr. Thompson, that
he has seen specimens attached to a spot not covered by water
during neap-tides. As a proof of its tenacity of life, Mr. Thompson
informs me that he accidentally kept some specimens in a box, in a
warm sitting-room, and found them alive seven days afterwards. This
same most accurate observer finds, however, that _B. balanoides_
is very susceptible to brackish water; he says, "that having kept
some specimens alive for a week in excellent health, the water being
changed once in thirty-six hours, they were one day killed instantly
by some water, though brought from the same part of the estuary as
usual, having been rendered brackish by much rain having lately
fallen." I may recall the fact, that _B. improvisus_ lives daily for
hours in absolutely fresh running water.

The _B. balanoides_ lives attached, often continuously coating
many square feet of the surface, to rocks, pebbles, wooden-piers,
littoral shells and ulvæ. The most northern point whence I have
received specimens, is in lat. 66° 34′ in North America, collected
by Mr. Sutherland; and the most southern point is Delaware Bay, in
the United States, in lat. 39°; I do not believe that this species
extends into the Mediterranean, for Ranzani (Mem. di Storia Nat.),
who particularly attended to the nature of the basis, was not
acquainted with any _Balanus_ having a membranous basis; and Poli
(Test. Ut. Siciliæ,) describes only two species thus characterised,
and these are manifestly _Chthamali_.

With respect to the rate of growth of this species, I am indebted to Mr. W. Thompson for the following note:--

"Sept. 29, 1848.--I examined a great number of Balani, in reference
to the growth made by them during the present season, and found it
to average three lines in diameter, and at most four lines. I saw a
few minute specimens, only one line in diameter, showing that the
species continued to breed until lately: these latter were probably
not more than four weeks old. The young of the present year are
plainly distinguished from the older ones, by their pure white colour
and fresh appearance. Judging from the size of this year's specimens,
and of the older ones on the same stones, I am of opinion that the
term of life of the species is two years. Of the older shells, which
I examined and found living in the spring, nine tenths are now dead,
the walls only remaining, the opercular valves having been washed
away."

Mr. Thompson goes on to say, that the individuals which had, on July 3, a basal diameter of from two and a half to three lines, had attained, by the 30th of September, a diameter of four and a half lines, this being here the maximum size of the species.

30. BALANUS CARIOSUS. Pl. 7, fig. 3 _a_-3 _e_.

LEPAS CARIOSA. _Pallas._ Nova Acta Acad. Scient. Petrop. tom. ii
(1788), p. 240, Tab. 6, fig. 24.

_Parietes thick, formed by several rows of unequal-sized pores. Tergum narrow, with the apex beaked, and spur sharply pointed._

_Hab._--Columbia River, west coast of North America, Mus. Brit.
and Cuming; Behring Straits (Capt. Kellett); the Kurile Islands,
according to Pallas. Attached to shells, and to each other in groups.

_General Appearance._--Shell steeply conical, with a rather small
oval orifice; or cylindrical, with a large rhomboidal and little
toothed orifice. Colour dirty white. Surface either simply rugged,
or more commonly covered by numerous, narrow, extremely prominent,
longitudinal plaits; from the manner in which these overlap each
other, the shell almost appears as if thatched with straw. The
upper corroded part of the shell usually exhibits a cancellated
and finely punctured surface. The radii are generally very narrow,
forming towards the base of the shell a mere narrow ribbon to each
compartment, and often hardly distinguishable; but in one specimen
they were of considerable width: in the former case, the alæ are
often widely exposed. The largest specimen which I have seen was 1.5
of an inch in basal diameter, but Pallas gives 2.2 as the measurement
of a specimen from the Kurile Islands.

The opercular valves are united to each other and to the shell by
unusually strong membrane; and the upper parts of both valves, in all
the specimens seen by me, have been much disintegrated. The _Scutum_,
in old specimens, is faintly striated longitudinally, but in some
there is hardly a trace of this: the occludent margin is furnished
with a few large knobs, not corresponding with every alternate line
of growth (as is usual with other species), but with every fourth or
fifth line. Internally, the articular ridge is moderately prominent
(in young specimens more prominent) and reflexed. The adductor
ridge is sharp and prominent; in the upper part it is confluent
with the articular ridge, but in young specimens can be seen to be
distinct; in the lower part it borders a large deep cavity for the
lateral depressor muscle, in the middle of which there is a very
slight longitudinal ridge; this cavity sometimes is almost closed or
arched over in its upper part. In one specimen, the basal margin of
the scutum was deeply hollowed out in the middle. The _Tergum_ is
remarkably narrow, with its apex produced into a triangular beak,
hollow within, and sometimes faintly tinged purple. A deep, closed,
longitudinal furrow runs down the valve. The spur is long, remarkably
narrow, and pointed. Internally, the spur is produced up the valve
as a ridge: the inflected scutal margin, and the prominent articular
ridge, are both nearly straight, and parallel to the spur. The crests
for the depressores are sharp and very prominent.

The _Parietes_ are very thick and strong: unlike every other
species of the genus, they consist of several very irregular rows,
of unequally sized, round or angular tubes (3 _b_). These tubes or
pores are generally short, and are at frequent intervals crossed by
transverse septa; they often rather deserve to be called cells than
tubes. New tubes are formed along the inner as well as along the
outer lamina. They are lined by dusky purple corium. The internal
surface of the parietes is smooth in the upper part, and in the
lower, it is reticulated by slight, irregularly branching ridges.
The carinal internal margin of each compartment projects a little,
as in the case of _B. crenatus_ and _balanoides_. The lower edge of
the sheath is either hollow beneath, or is united to the walls. The
_radii_ in one specimen were broad, with slightly oblique, jagged
summits; generally they are extremely narrow, forming more ribbons
along the lower edges of the compartments, barely extending up as
high as the sheath. They can sometimes hardly, or not at all, be
seen, until the shell is disarticulated: in rather young specimens
the sutural edge is sometimes quite smooth; in old specimens the
lower part of the edge has coarse arborescent septa, with the
interspaces filled up solidly, whilst the upper part is smooth.
The _alæ_ are conspicuous from the outside, owing to the little
development of the radii; but owing to the diametric growth not
having been great, the part added during such growth is narrow;
the summits of the alæ are only slightly oblique: the sutural edge
is coarsely crenated, with the teeth denticulated or slightly
arborescent.

_Basis_ membranous.

_Mouth_: labrum with only four very minute teeth: mandibles with four
teeth; the third tooth broader than the first; the fourth small.
Maxillæ, with the two upper spines placed on a slight prominence,
beneath which there is a small notch. _Cirri_ of a very dark colour
(much injured): the segments of the first, second, and third pairs
very broad and short, protuberant in front, and most thickly clothed
with spines; the third pair is very little longer than the second
pair: the sixth pair (in a large specimen above one inch in basal
diameter) had the segments broader than long, each furnished with
seven pairs of spines.

_Affinities._--This species, though very distinct, evidently comes
near to _B. balanoides_, especially to _var._ (_a_). By merely
doubling or trebling the irregular rows of short tubes in the
walls of _B. balanoides_, with their reticulated inner lamina and
longitudinally folded outer lamina, we should have the structure
exhibited in _B. cariosus_. We have seen, also, that in _var._
(_a_) of _B. balanoides_, the spur of the tergum is remarkably
sharp, as in _B. cariosus_. This species, also, in a very marked
manner approaches in many characters, especially in the opercular
valves, in the cirri, and to a certain extent in the shell and
basis, to _B. flosculus_, and even in external appearance to _var.
sordidus_ of the latter--an inhabitant of the opposite extremity
of the continent, namely, of Tierra del Fuego. Again, the tergum
to a certain extent, and the scutum in a singular manner, resemble
these valves in _B. nubilus_, showing an unequivocal affinity to
that species. With respect to the most remarkable character of the
species, namely, the several irregular rows of tubes or pores in the
walls, it deserves notice that in _B. crenatus_, which is certainly
closely allied to _B. balanoides_, the longitudinal septa sometimes
divide near the outer lamina, thus giving rise to a few additional
tubes. Of the above several species, to which our present species is
allied, _B. flosculus_ stands in the next section, and _B. nubilus_
and _crenatus_ in the last: hence we see that _B. cariosus_ has
singularly divergent affinities. The peculiar structure of the
parietes, together with the general appearance of the shell, made me
at the first moment suppose I was examining a Tetraclita (or Conia of
Leach); hence, also, it has arisen, that _Lepas cariosa_ of Pallas
has often been quite erroneously given as a synonym of _Tetraclita
porosa_.

31. BALANUS DECLIVIS. Pl. 7, fig. 4 _a_-4 _d_.

_Parietes solid; rostrum nearly twice as long as the carina or carino-lateral compartments, hence the basis is oblique. Tergum with the spur truncated, half as wide as the valve._

_Hab._--West Indies; Mus. Brit.--Jamaica, imbedded in a sponge; Mus.
Cuming.

This is a remarkable species; when first seeing it imbedded in numbers in a sponge, I did not in the least doubt but that it was an Acasta: on examination, however, it is found to have a membranous basis, and therefore cannot by the definition enter into that sub-genus, to which, however, it is very closely allied. It differs from other sessile cirripedes very remarkably in the rostrum being nearly twice as long as the carinal compartments, so that the basis is always very oblique, or placed almost on one side; in this elongation of the rostrum, although in a different direction, we are reminded of _B. calceolus_ and its allies; and these latter we know can hardly be separated from certain species of Acasta. Hence the position of our present species in this section, is not natural; but I am unable to place it elsewhere, without breaking down every definition: it should stand somewhat isolated, on one side of a line of affinity connecting _Balanus calceolus_ and _navicula_ with _Acasta purpurata_.

_General Appearance._--The shell is thin, fragile, smooth, and
white, but covered to a considerable extent by a brown membrane,
which on the sheath and opercular valve is of a bright tint, and
clothed with bristles. Viewed laterally, the rostrum is seen to
be considerably bowed, and from its being nearly twice as long as
the other compartments, with its lower end bluntly pointed, the
basal margin of the whole shell is rendered very oblique, forming a
slightly concave line. The lateral compartments are rather longer,
and about one third broader than the carino-lateral compartments.
The rostrum, from terminating downwards in a blunt point, instead
of being square or truncated, as in all other Cirripedes, and from
the upper end being, as is usual, pointed, has, when disarticulated
from the other compartments, the shape of a boat. The parietes are
not at all porose: their internal surface sometimes shows traces
of longitudinal ribs, but sometimes there are none. The radii are
narrow, with their summits very oblique, and their sutural edges
smooth. The sutural edges of the alæ are likewise smooth. The largest
of Mr. Cuming's specimens was .2 of an inch in diameter; but a
disarticulated specimen in the British Museum must have been larger,
having a rostrum .3 in length. The _Basis_ is membranous.

The _Scuta_ are rather convex; they have their lines of growth
approximate, most finely crenated, so as to be very feebly striated
longitudinally. Internally, the articular ridge is pretty well
developed, its lower edge being very oblique; there is barely an
adductor ridge: the pit for the lateral depressor muscle is deep.
The spur of the _Tergum_ is placed close to the basi-scutal angle
of the valve; it is about half as wide as the valve, with the
lower end truncated: sometimes it may be rather said to be bluntly
pointed, owing to its carinal side sloping up to the basal margin.
The articular ridge is pretty well developed. The crests for the
depressor muscles are barely discernible.

_Animal's body_ unknown.

_Section_ F.

_Parietes and radii not permeated by pores; basis sometimes permeated by pores, sometimes not permeated, sometimes excessively thin and hardly distinguishable._

32. BALANUS HAMERI. Pl. 7, fig. 5 _a_-5 _c_.

LEPAS HAMERI. _Ascanius._ Icones rerum naturalium, Tab. 10, 1767.

---- TULIPA. _O. F. Müller._ Prodromus. Zoolog. Dan. 1776; sed non
_L. tulipa_, in Poli, Test. ut. Siciliæ; neenon _B. tulipa_, in
Bruguière, Encyclop. Method; neenon _B. tulipa_, in Sowerby,
Genera of Shells.

---- TULIPA ALBA. _Chemnitz._ Syst. Conch. Tab. 93, fig. 832.

---- FOLIACEA. _Spengler._ Skrivter of Naturhist. Selskabet, 1 B.
1790.

BALANUS CANDIDUS. (Tab. emendata) _Brown._ Conch. Great Britain
(1827), Tab. 6, figs. 9 and 10, et 2d edit. Tab. 54, figs. 9-12.

---- TULIPA. _Lyell._[98] In Phil. Transact., 1835, p. 37, Tab. 2,
figs. 34-39.

[98] Sir C. Lyell remarks that this is apparently the _B.
Uddevallensis_ (Linn.) of Swedish lists of fossils. Prof. E. Forbes
has shown (Mem. Geolog. Survey of England, vol. 1, p. 364) how this
name arose, from a short description, prior to the introduction of
the binomial system, "Lepas quæ Balanus Uddevallensis," given by
Linnæus in his Wast-Gotha Resa, in 1747.

For the reference to Ascanius' work, which is on the binomial
system, and subsequent to the 10th edit. of Linnæus, in 1758, I am
greatly indebted to Mr. Sylvanus Hanley. Had it not been for this
gentleman, I should have used Müller's name of _B. tulipa_ as the
first name.

_Shell white: radii with their oblique summits smooth and arched; sutural edges smooth: basis solid. Scutum feebly striated longitudinally: tergum with the spur narrow._

_Hab._--Coast of Yorkshire; Scotland; Galway, Ireland; Isle of Man,
and Anglesey, twelve fathoms. Generally in deep water; not very
common. George's Bank, Massachussetts, United States; Mus. Aug.
Gould. Iceland, Finmark, and the Faroe Island, according to Spengler.
Attached to crustacea, mollusca, stems of fuci, and stones; often
associated with _B. porcatus_ and _crenatus_.

_Fossil._--In glacial deposits at Uddevalla in Sweden, and Beaufort
in Canada; Mus. Lyell. Banks of the Dwina, Russia; Mus. Murchison.
Greenland, "in blue clay," according to Spengler. Red Crag (Sutton)
Mus. S. Wood.

_General appearance._--Shell tubulo-conical, very smooth, white,
generally more or less covered by yellow thin membrane: orifice
large, sub-triangular: radii moderately broad, with their more
or less oblique summits slightly rounded and smooth; from this
circumstance the shell has been justly compared to the half-opened
flower of a white tulip. Specimens often exceed an inch in basal
diameter; I have seen one from Scarborough two inches in diameter
and one and three quarters in height: another specimen was 1.6 in
diameter and 3 in height. The specimens in the glacial deposits seem
even to have acquired larger dimensions, one from Uddevalla being
nearly four inches in height.

_Scuta_, elongated, flat, feebly striated longitudinally:
internally, articular ridge short, moderately prominent: adductor
ridge, confluent in the upper part with the articular ridge,
running straight down and forming a rather large cavity for the
lateral depressor. _Terga_ feebly striated longitudinally, with a
longitudinal furrow, having the sides, in old specimens, partly
closed in: the basal margin slopes much towards the spur, which is
rather long and narrow, with its end rounded: it is placed at about
its own width from the basi-scutal angle. Internally, articular
furrow narrow; crests for the depressores moderately prominent, but
in a variable degree.

_Compartments_: these are unusually thin, and separate easily: the
parietes are finely ribbed longitudinally on their insides; the
bases of these ribs being just perceptibly denticulated. _Radii_,
with their summits oblique (usually at about an angle of 45°),
slightly arched and quite smooth: the smoothness is produced by the
edge being a little inflected: sutural edge quite smooth, without
even a trace of septa or denticuli. _Alæ_ oblique, generally rather
less oblique than the summits of the radii: sutural edges smooth,
with an excessively fine linear furrow running along the edge, a
little towards the inner side, and filled with a yellow ligamentous
substance: a furrow of this kind I have seen in no other species.

_Basis_, solid, not permeated by pores; either smooth, or slightly
furrowed in lines radiating from the centre.

_Mouth_: labrum with scarcely perceptible minute bead-like teeth
thinly scattered along the edge. _Palpi_ and _outer maxillæ_ rather
sparingly clothed with hairs. _Mandibles_ with teeth rather sharp;
the fourth and fifth teeth small, but well developed; inferior angle
pointed with fine spines. _Maxillæ_ with a deep notch under the two
upper great spines. _Cirri_, the first pair is short, with rami of
nearly equal length: the segments are not protuberant in front either
in the first or second pairs. In the posterior cirri, the segments
bear four pairs of spines, with a tuft of rather long intermediate
spines: in young specimens there are only three pairs: the spines in
the dorsal tufts are short and thin.

When the shell is disarticulated, this species cannot be confounded
with any other; but judging by external characters alone, it may
sometimes be very easily confounded with _B. eburneus_, and I have
received the two species under this one name from Massachussetts:
generally _B. Hameri_ may be distinguished from _B. eburneus_ by
the smoothness of the summits of its radii, and by the so-called
epidermis being of a darker yellow.

With respect to the fossil specimens from the glacial deposits,
I have little to add; I have seen one from Uddevalla, as already
remarked, four inches in height, and a lateral compartment broader by
one fourth than the same compartment in any recent specimen. As Sir
C. Lyell remarks (Phil. Transact.), the compartments are always found
separated, which is accounted for by their weak union in a recent
state. This species, when fossil, is usually associated with its
deep-water congeners _B. porcatus_ and _crenatus_, as at the present
day.

I must here mention that I have examined a considerable number of
_separated_ compartments, without opercular valves, brought from
Barbados, in the West Indies, showing the existence there of a
closely allied or possibly identical species. The only difference
which I can point out in these compartments is, that the parietes
are rather thicker, and the radii rather narrower, with more oblique
summits: some of the compartments are two inches in length. It seems
very improbable that the true _B. Hameri_ should extend to the West
Indies, but after what has been seen in the case of _B. crenatus_,
this is possible.

33. BALANUS AMARYLLIS. Pl. 7, fig. 6 _a_-6 _c_.

_Shell striped or clouded with pinkish-purple, or quite white; radii narrow, with their oblique summits smooth or arched: basis porose. Scutum plainly striated longitudinally: tergum with the spur narrow._

_Var._ (_a_):[99] _bright rosy pink, not distinctly banded
longitudinally_. Hab. North-east coast of Australia.

_Var._ (_b_): _snow white, glossy; orifice deeply toothed_.

[99] This variety perhaps is the _B. roseus_ of Lamarck, as
figured in Chenu, 'Illust. Conch.' Tab. 2, fig. 9; but as Lamarck
does not even notice such conspicuous external characters as the
longitudinal striæ on the scuta, and the smooth rounded edges of
the radii, it is impossible to identify his species.

_Hab._--Mouth of the Indus; East Indian Archipelago; Philippine
Archipelago; Moreton Bay, and the north-east coast of Australia.
Attached frequently on ships' bottoms, associated with _B.
tintinnabulum_ and _amphitrite_. Sometimes attached to _Gorgoniæ_
with _B. calceolus_.

_General Appearance._--Shell steeply conical, with the orifice
sub-rhomboidal, moderately large, very slightly, or deeply notched:
surface very smooth: white, longitudinally banded with pinkish or
leaden purple, with sometimes a purplish, sometimes a yellowish tint,
the latter owing to the persistent epidermis; the bands are pale,
and often fade away in the lower, and sometimes in other parts of
the shell; the epidermis is generally more persistent on the narrow
rounded radii than on the parietes, and hence the radii are generally
yellowish. The opercular valves are pale dull purple: the sheath is
darker purple, with the exception of the portions of the alæ added
during the diametric growth, which are of a dead white, and are
externally conspicuous. The scuta are striated longitudinally. I
may remark, that, excepting the narrowness of the radii, with their
quite smooth, rounded and very oblique summits, some specimens are
hardly distinguishable, in external aspect, from varieties of _B.
amphitrite_. If the specimens from the north-east coast of Australia,
of which I have seen many (but unfortunately only one small one had
its opercular valves), form, as I fully believe, merely a variety; it
is characterised by its nearly uniform beautiful rosy pink, without
any _distinct_ longitudinal bands: of these specimens I have seen
one two inches in basal diameter, and three in height: of ordinary
duller-coloured striped specimens, the largest was 1.7 in basal
diameter. Of the perfectly white _var._ (_b_), I have seen several
specimens, the largest being .6 of an inch in diameter: these have
a somewhat peculiar aspect, but I have met with only one specimen
with opercular valves, and that was extremely young: I at first
considered this form as specifically distinct; but I can point out,
after careful examination of the whole shell, operculum, and internal
animal of the young specimen, no sufficient diagnostic characters.

_Scutum_, plainly striated longitudinally, with the striæ dividing
the prominent lines of growth into squarish beads: internally, the
upper part of the valve is roughened: the articular ridge is short,
remarkably little prominent, and not reflexed; the adductor ridge
is blunt and little prominent; sometimes it is almost confluent
with the articular ridge: there is a deep but variable depression
for the lateral depressor muscle; and in young specimens of _var._
(_a_) it was almost absent. _Tergum_: the surface exhibits traces of
longitudinal striæ: there is a deep longitudinal furrow, with the
sides folded in and quite closed in full grown specimens: the scutal
margin is considerably curved towards the scutum. The spur is long
and narrow, with the end bluntly pointed, placed at rather above its
own width from the basi-scutal angle; the basal margin slopes but
little towards the spur: the crests for the depressores are feebly
developed.

_Parietes_: their internal surfaces are strongly ribbed
longitudinally, with the basal ends of the ribs coarsely
denticulated, and with the denticuli extending close to the outer
lamina. The radii are generally narrow, but their width varies;
their summits are very oblique, smooth, rounded, and inflected, with
the lines of growth, in the uppermost part, curving inwards; their
sutural edges, in the upper inflected portion, are quite smooth,
without septa; in the lower and larger portion, the edge is crenated
with excessively fine teeth or septa, not denticulated: the radii,
like the parietes, have no inner lamina: the recipient grooves in
the opposed compartments are smooth, and are in the lower part of
the shell of unusual depth. The _alæ_, differently from the radii,
generally have their summits very slightly oblique, but sometimes
they are highly oblique: their sutural edges are most finely
crenated. The _basis_ is generally flat, sometimes cup-formed; it is
permeated by pores, crossed by transverse septa; and sometimes there
is an underlying cancellated layer.

_Mouth_: labrum with either six very small teeth, or with none.
_Mandibles_ (Pl. 26, fig. 5), with the third tooth a little thicker
than the first; fourth and fifth teeth small, but quite distinct.
_Maxillæ_ (Pl. 26, fig. 7), with the inferior part forming a square
step-formed projection, bearing, one behind the other, two spines
as long as the upper pair; in a young specimen of _var._ (_a_) this
step-formed projection was absent.

_Cirri_: first pair with the rami unequal by about four segments: the
shorter ramus has the segments very protuberant in front, thickly
clothed with strongly serrated spines; the second cirrus has segments
moderately produced; the third has them produced only in a slight
degree. The pedicels of the second and third cirri have dorsal tufts
of spines, but not a hairy plate prolonged over the thorax. The
posterior cirri have segments broader than long, bearing only two
pairs of nearly equally long spines; and between each pair there is a
small intermediate tuft. The penis has the usual basi-dorsal point.

_B. amaryllis_ is a distinct and well-defined species, more nearly related to _B. Hameri_ than to any other form.

34. BALANUS ALLIUM. Pl. 7, fig. 7 _a_-7 _d_.

_Shell faintly tinged with purple: radii broad, with their summits not oblique: basis not porose. Scutum with the lines of growth crenated: tergum with the spur extremely short, truncated, broad as half the valve._

_Hab._--Raine's Islet, Barrier Reef, Australia, Mus. Stutchbury. Hab.
unknown, attached to and coated by Porites. Mus. Brit.

_General Appearance._--Shell conical, smooth, but with the lower part
sometimes narrowly ribbed in lines corresponding with the internal
longitudinal ribs; tinted pale peach-blossom purple, owing to the
sheath being finely so coloured; or wholly white. Radii broad, white,
square on the summit, hence orifice entire, ovate passing into
rhomboidal. The parietal portion of the carino-lateral compartments
extremely narrow, about one eighth of the width of the parietes of
the lateral compartments. Basis concave, partially imbedded in the
coral. Largest specimen .35 of an inch in diameter.

There are some specimens in Mr. Cuming's collection which appear to
belong to this species, and are certainly very closely allied to it,
but not having the opercula, cannot be identified positively; the
shell is flatter, with the walls strongly ribbed up to the orifice,
which is more rhomboidal: the basis is much more cup-formed and more
deeply imbedded in the coral; but these differences by themselves are
by no means sufficiently diagnostic.

_Scutum_: the lines of growth are crenated, causing the surface to
be very obscurely striated longitudinally: the articular ridge is
very prominent, as can be best seen from the outside, and runs down
the whole length of the tergal margin with a very regular curve, and
hence differs from the articular ridge in the foregoing species. The
adductor ridge is either absent, or very indistinct, and parallel
to the articular ridge: there is a deep little pit for the lateral
depressor muscle. _Tergum_ (7 _d_), with the apex somewhat produced
or beaked, and tinged purple: external surface almost flat, without
any longitudinal furrow: scutal margin curved. Spur very short,
placed quite close to the basi-scutal angle of the valve; broad as
half the valve; lower end square. Internally, the articular ridge is
prominent only in the uppermost part of the valve: crests for the
depressores very feeble.