_Concluding Remarks._--In comparing the capitulum of the hermaphrodite with that of the complemental male (Pl. VI, figs. 6 and 3), we must be struck with the differences in their shape, in the number, relative sizes, and forms of the several valves. It should, however, be borne in mind, that the scuta and carina in the hermaphrodite at first grow exclusively downwards; so that if we remove the upper portions subsequently added, the difference in shape in these valves is not so great as it at first appears. The rostrum in the male is of much larger relative size; whilst of the upper latera there is not a trace, although in the hermaphrodite these valves are larger than the rostrum. The terga, compared with those of the hermaphrodite, differ more essentially than do the other valves; and the manner in which the primordial valves project, shows that from the first commencement of calcification, the lines of growth have followed an unusual course. The great breadth and shortness of the terga is evidently related to the shortening of the whole capitulum, and the transverse position of the orifice; and this shortening of the capitulum, no doubt, is rendered necessary for its reception and protection within the shallow furrow between the scuta of the hermaphrodite. Finally, if we compare the internal parts of the hermaphrodite and male, the differences are considerable, though partly to be accounted for by the youth of the latter: the form and position of the labrum, and the distance between the first and second pair of cirri, is the same in both; but the mandibles and maxillæ differ considerably. To put the case as I have before done, if a specimen of one of these parasites had been brought to me to class without any information of its habits,--the downward direction of growth in all the valves, the presence of a rostrum, the villose outer integument, all the details of the prehensile antennæ, the form of the animal’s body, and the position of the labrum, would have convinced me that, though a quite new genus, it ought to have stood close to Scalpellum, and nearer to it than to Ibla. 6. SCALPELLUM VILLOSUM. Pl. VI, fig. 8. POLLICIPES VILLOSUS on Plate (TOMENTOSUS in text). _Leach._ Encyclop. Brit., Suppl., vol. iii, 1824, Pl. lvii. ---- VILLOSUS.[59] _G. B. Sowerby._ Genera of Shells, Pollicipes, fig. 3, 1826. CALANTICA HOMII. _J. E. Gray._ Annals of Phil., vol. x, p. 100, 1825. [59] As Mr. Sowerby has adopted the name _villosus_, I have followed him; though as _tomentosus_ is used through some mistake by Leach in the text, both names have equal claims as far as priority is concerned. In Lamarck, ‘Animaux Sans. Vert.,’ the _P. villosus_ of Sowerby is made synonymous with _Anatifa villosa_ of Brugière, which is certainly incorrect, although the _A. villosa_ of this latter author is not positively known.