A Monograph on the Sub-class Cirripedia (Volume 2 of 2)

ULUM. Linn. Sys

hil. Transact., vol. 50, 1

Neues. Syst. Conch., 8 B. (1

B. tulipa alba, in Chemnitz; neenon B. tulipa, O. F. Mülle

Genera of Recent and Fossil

r?ter. Einleitung Conch.

var.) Gmelin.

TA. W. Wood. General Conchology, 1815, Pl. 6,

BULUM. Chenu. Il

u. Illust. Conch., Tab. 6, fi

) Sowerby (!). Min. C

es; but he confounds some forms certainly distinct under

e generally entire, sometimes toothed. Scutum with the articular ridge broad and reflexed.

al or tubulo-conical; smooth or moderately ribbed longitudinally; colours varying from purplish-

face of the scuta impressed with small square holes, arrange

ely ribbed, ribs flexuous; either smooth or rugged; pale chocolat

purple with broad snow-white ribs; sheath bright chesnut

gular rough projections, or with short, sharp, needle-like points; scuta with their exte

shell rather thin, with long, upcurved, nearly cylindrical, very sharp poi

inally with varying shades of pink; radii tinged with purple; scutum sometimes as in var. communis, sometimes with its basi-tergal corner much cut off, with the adductor ridge prominent, the pit

d and freckled with white; scutum, with a broad, hooked, articular ridge, with an extremely sharp plate-like

lish-blue longitudinal lines; sheath with the internal surface of the rostrum and lateral compartments much darker c

al lines; sheath with the internal surface of the rostrum and lateral compartments dull blue, whilst the corresponding parts of the carina and carino-lateral compartments are white; scu

toothed; shell conical or tubulo-conical, smooth, or rugged; colour dull purplish-lilac, with the tips of the parietes and a band along on

s; East Indian Archipelago; Sydney, Australia, attached to Lepas anserifera, adhering to a floating cane; Peru; Galapagos Islands; West

s. S. Wood and J. de C. Sowe

ing the vacillations which I have experienced on this subject, that beginning with the impression, that the above three varieties were really distinct species, after going over the several immense collections of specimens placed at my disposal, I came to the conclusion that the above three, and several other forms presently to be described, were only varieties; yet after an interval of some months, having to look at some of these specimens again, I could not but think that I had come to a false conclusion, and so went into all the details again, and satisfied myself that I had followed a right course; after another interval, I had to repeat the same process, and even now I can never look at a group of the beautifully coloured shells w

ven in the Introduction (p. 102) in regard to certain monstrous specimens of Bal. balanoides having been apparently impregnated by adjoining individuals, that the varieties may interbreed, and so produce numerous intermediate forms. Whether or not this could take place, I am inclined to look at these two species, as in an almost analogous condition with our domestic animals, which give rise to such infinitely numerous varieties. It appears to me probable, that several of the varieties kee

with purple, to dark, inky purple, more or less striped, longitudinally, with white or pale tints; rarely the shell is of the brightest rose-colour, either uniform or longitudinally striped; sometimes it is pale purplish, or dark blue; and sometimes dark chocolate-purple: the ribs, when present, are generally more or less white, sometimes snow-white. That there is much variation in colour, and in the prominence of the longitudinal ribs, is quite certain, as the two sides of the same individual sometimes differ greatly in these respects. The radii are generally rather darker coloured than th

r scuta are sometimes deeply pitted in radiating lines. Their colours are generally pale. I have seen specimens attached to kelp from the Cape of Good Hope, with thei

communis (Pl. 2, fig. 1 a, 1 d, 1 e). The articular ridge (1 c, 1 e) is broad and much reflexed; and often, but not always, distinctly hooked (1 f). The adductor ridge is confluent with the articular ridge, and runs straight down the valve, bounding the cavity for the depressor muscle; generally the adductor ridge is blunt, and so little prominent as barely to deserve notice; but I have seen it sharp and prominent in one specimen of var. communis, and it is generally prominent in var. coccopoma (1 f), and most remarkably so in var. concinnus (1 g). The cavity

its own width from this angle. The basal margin (1 i), on opposite sides of the spur, either forms a nearly straight line, or the scutal portion descends lower than the carinal portion, and curves very regularly towards the spur; this is the case in var. d'Orbignii (1 n), and in some specimens of var. occator. The carinal half of the basal margin generally forms an angle with the spur of only a little above a rectangle. The spur varies a little in length and breadth, but never exceeds one fourth of the greatest breadth of the valve. The scutal margin is broadly inflected, the infle

ip to tip of the adjoining compartments, that is, their summits are parallel to the basis; but in three not common varieties, viz., vars. intermedius, occator, and d'Orbignii (the former of which at least must, without the smallest doubt, be ranked as a mere variety), their summits are oblique. I have occasionally met with specimens of var. communis with oblique radii; and this is not very infrequent in young shells. Exteriorly the radii are generally smooth, but sometimes finely ribbed horizontally, owing to the projection of the septa. The a

t 19 segments in the longer ramus, to 16 in the shorter. The segments in the latter have their anterior surfaces very protuberant. The second pair is short, with the anterior surfaces of the segments protuberant. On the thorax (Pl. 25, fig. 1), on each side, at the bases of third pair of cirri, there is a projecting membranous plate fringed with fi

ving at our ports, from West Africa, the West Indies, the East Indian Archipelago, and China. It is generally associated with B. amphitrite and amaryllis. I have already stated that, on the bottoms of vessels, the different varieties are generally grouped together; and this makes me believe that they are local. In Mr. Stutchbury's collection there are numerous specimens taken from a ship which first went

is species. The specimens named by Mr. Sowerby, in the 'Mineral Conchology,' as B. crassus, and which I have seen through the kindness of Mr. J. de C. Sowerby, also belong to thi

iet

e that some of the coarsest and strongest specimens which I have seen were said to have been attached to a surface of iron. I have seen two large lots of var. zebra (1 g), taken by Mr. Stutchbury, from the bottoms of ships, arriving from Bengal and China, and in bot

nts formed by the upturned lines of growth, have a very remarkable appearance, from being arranged in quite straight radiating lines. This structure is evidently caused by the same tendency which produces on the walls the sharp, upturned, irregular points; but it is singular that the scuta are smooth in some specimens with very rough parietes; and, on the other hand, bristling with the symmetrically arranged, hood-like projecti

ove specimens, externally were smooth; the adductor ridge was rather more distinct from the articular ridge than in any other variety; and the terga rather more plainly beaked. The tubular, up-curved, calcareous spines sometimes occur only on one side of the shell, and often only in the lower part. These spines are often coloured brighter than the walls. Their presence cannot be accounted

f specimens taken off a vessel, on the west coast of South America, almost identical in external appearance with those in my possession, but rather more rugged. Mr. Stutchbury has sent me some specimens from a ship, direct from China, which are rather paler pink, and more striped, and come near to some ordinary varieties of B. tintinnabulum. The scuta (Pl. 2, fig. 1 f) in the above three sets of specimens agree in having the adductor ridge more developed, and the pit for the lateral depressor muscle deeper than is usual. The tergum (1 l,

ominent; and the rostral depressor muscle, instead of being lodged in a little cavity formed by the folding over the occludent margin, has, in addition, a small plate on the under side, which tends to convert the pit into a tube. The tergum exactly resembles that of var. communis. The segments in the sixth cirrus bear six, instead of four, pairs of spines,-a circumstance which I have noticed only in some young specimens of var. communis, from the Cape of Good Hope. From these several peculiarities, until quite lately, I resolved to keep this form specifically distinct; but I have finall

rned, approaching closely in structure to var. concinnus,-all three from the west coast of America. Hence I was at one time led to believe that there existed a species on this line of coast, which represented B. tintinnabulum, and which varied in external shape and colour in an analogous manner to that species. But as the ope

have seen only two groups of specimens in Mr. Cuming's collection: the chief interest in this vari

lly and internally, exactly the same peculiar appearance. In var. intermedius, I found the summits of the radii equally oblique, and the general colouring nearly the same, and more especially a close approach to the singular circumstance of the sheath differing in colour towards the opposite ends of the shell. So that the position of the spur of the tergum was the chief remaining character; and this evidently varied considerably in the four or five specimens examined by me, being either its own width, or much less than its own width, from the basi-scutal angle: the outline, also, of the small portion of basal margin, betwee

was led to think this form specifically distinct. But the colour does not differ from that of some other varieties of B. tintinnabulum; the circumstance of the colour being uniform or not striped, is common to the sub-varieties of several varieties, and the white tips to the parietes, and the white borders to the radii, result simply from the shell, whilst young, having been wholly white, and this is not rarely the case with var. communis. Dismissing, therefore, colour, it will be found that hardly any other characters remain by which this form can be separated from var. occator; in both the summits of the radii are oblique, in both the sheath is coloured in nearly the same manner, in both the opercular valves,