[40] I owe to the kindness of Professor Owen, an examination of these specimens, and information regarding them.

Capitulum, with the membrane very thin; summit obtusely pointed. Valves linear and thin.

Scuta, elongated, flat, with the upper projecting lobe rather more acuminated than the lower, and equalling it in length; lateral lobe not wider than the lower, and about as long as it, forming an angle of about 55° with the upper one.

Terga, of somewhat variable length, generally about half as long as the carina, narrow, and of nearly equal width throughout; lower point sharp; externally convex; internally solid, with a trace of a central depressed line; the upper fourth part generally a little bowed out of the plane of the lower part, and abruptly bent at rather above a right angle along the occludent margin of the orifice. These valves are situated at about half their own length from the upper points of the scuta.

Carina considerably arched, extending to the lower points of the terga, or running up between them for even half their length; equally narrow throughout; scarcely broader than the terga; both points rounded; internally concave; the lower point does not extend as far down as that of the lower lobe of the scuta.

Peduncle, narrow, shorter than the capitulum, which, in the largest specimen was 4/10ths of an inch long. Longitudinal purple bands appear to have originally existed on the peduncle.

Filamentary Appendages, trophi and cirri all similar to the same parts in C. virgata; but perhaps the anterior faces of the segments in the posterior cirri are rather less protuberant; perhaps also the first cirrus is rather shorter in proportion to the sixth cirrus.

Variety (monstrous).—Amongst the specimens, I found one very young one, in which the scuta had not upper lobes, so that in outline they exactly resembled the scuta in the quite distinct C. aurita: there was not even a rudiment of a carina: the tergum, on one side, was externally bordered by a projecting, semicircular, calcified disc; and the upper points of both terga showed only traces of the rectangular projection, which is the chief characteristic of C. Hunteri. From these traces alone, and from the specimen being mingled with the others, do I here include this variety.

General Remarks.—I have very great doubts whether I have acted rightly in considering this as a species; but as there were many specimens, old and young, all differing remarkably from the common species, this form anyhow deserves description. The points by which it can be distinguished from C. virgata, are—the almost rectangular manner in which the upper portion of the tergum is bent outwards and along the orifice of the sack—the narrowness of all the valves, and especially of the lateral lobes of the scuta,—and lastly, the greater curvature of the carina, which in some specimens runs up far between the terga; had this last character been constant, it would have been an important one, but such is far from being the case. Great as are these differences in the valves, and though common to many specimens, they are not sufficient to convince me that it is a true species, and I should not be at all surprised at varieties, intermediate between it and the common form, being hereafter found;—had a name not been already attached to it, I should not have given one. In the monstrous variety described, we see to what an extent the valves may vary. The C. Hunteri approaches nearest to the var. of C. virgata, called by Leach Cineras chelonophilus, for in both, the top of the capitulum is bluntly pointed and the terga are solid within; in the Var. chelonophilus, the terga and carina are minute, whereas here, though very narrow, they are much elongated. Certainly C. chelonophilus has almost as strong a claim to rank as a species as C. Hunteri; but, in the former, by the aid of other varieties, the differences were almost reduced to the peculiarities in the terga—the valves, the most subject to variation. In C. Hunteri we have other differences, and the form of the terga is even still more peculiar. I have, therefore, provisionally attached to it the specific name by which it is designated in the Museum of the College of Surgeons. From having been long kept in spirits, all aid from colour is lost.

Genus—Alepas. [Pl. III.]