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Show C70 SIR C. ELIOT ON NUDIBRANCHS [J u n e 19, the large branchiae. Pease's T. jricla (Amer. Journ. of Conch. 1871, vol. vi. p. 301) is perhaps a synonym, since it has a similar coloration and the " branchial star large . . . . wider than the body." Perhaps also Riippell & Leuckart's Doris impudica (1828) is the same species. If this can be proved, the specific name has priority. The Newcastle collection contains a good coloured drawing by Kelaart, which is not reproduced here since it has already been published in black and white in the Ann. & Mag. of Nat. Hist. (I. c.). See also the coloured edition of H. & A. Adams's ‘ Genera of Recent Mollusca,' pi. cxxxvii. fig. 14. K a l in g a A. & H. This remarkable genus was regarded by its discoverers, Alder and Hancock, as intermediate between Euplocamus and Plocamo-pherus, but it does not possess the characteristic conformation of the radula and prostate which distinguishes those genera. There can be no doubt, however, that it belongs to the Polyceridae. Externally it differs from most members of the family in its somewhat doridiform shape, the absence of a tail, and in having its branchiae entirely separate from one another, much as in Hexabranchus * and Bathydoris. In the Dorididae phanero-brancliiatae, where the gills are not retractile, the complete isolation of the separate plumes does not necessarily imply any considerable structural change, but it may be a survival of an arrangement which is more primitive than the symmetrical circuit of united branchiae. The genitalia, so far as they are known, seem to be of the type found in Polycerci and its allies, but the shape of the glans penis is unusual and resembles that of Phialodoris. The radula differs from those of all known nudibranchs. It is very broad and composed of very numerous tricuspid teeth. The specimens here examined indicate that the buccal organs are of extraordinary size and strength, though it is hard to say wiiat may be their natural position and modus operandi. K a l in g a o rnata A. & H. (Plate XLYII. fig. 2 .) (A. & H. I.e. pp. 134-6. Bergh in Semper's Reisen, xvii. pp. 959-962. Farran, 1. c. p. 347.) The Newcastle collection contains three poorly preserved specimens, which are the types used by Alder and Hancock for their description published in 1864, and also a very large specimen, relatively well preserved, and labelled " Sir W. Elliot, Madras, '* The descriptions of the gills of Hexabranchus are often most misleading, for they state that the organs are retractile into separate cavities or pockets, the natural meaning of which is that each branchia has a separate parmanent cavity into which it can be retracted. But in reality there are no such cavities. The plumes are con-tractile separately, and when they contract, the skin, being soft, forms a temporary hollow at their bases. But they do not disappear into a pocket, and when they spread out again the hollow vanishes. |