150 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



find that, in internal as well as external characters, they agree with 

 the other members of the genus. The body is chocolate colour, with 

 yellow ocelli ; the dorsal margin bears three pairs of processes which 

 show little sign of ramification, but those on the oral veil are said to 

 have been branched in life, and the crest on the tail was a great fleshy 

 hump. The formula of the radula is 21 x 9 (or 10) + 3 . . 3 + 9 

 (or 10). The rhachis is very wide and divided into areas by transverse 

 divisions. The characteristic reticulate prostate is well developed. 



Probably all the species can swim. This is specially recorded of 

 P. Maderce, P. Ceylonicus, and P. maculatus. 



Plocamophertts Madera (Lowe). PI. XIV, Figs. 8, 9. 



Peplidia Maderce, Lowe : Proc. Zool. Soc, 1842, p. 51. 



Mr. Crossland's notes on the living animal are as follows : — 

 "Two specimens from the bottom of a large rowing boat which 

 was covered with Hydroids and Polyzoa. Larger specimens about 

 2i inches long, of a high, narrow shape. Foot narrow, but can adhere 

 strongly. Tail especially high, and has a kind of crest along the top. 

 Gills can be counted as either 5 or 3 ; tripinnate. Finest branches 

 nearly colourless ; very mobile and contractile, but not retractile into 

 a pocket. Body bears three pairs of branched sand-coloured processes, 

 about ^ inch long; branches very small, pointed, and with bright 

 yellow tips (this colouration only visible under a lens). Laterally 

 there are a few scattered papillae of the same kind, but smaller. The 

 dorsal ones are placed thus: 1st pair one-third distance between 

 rhinophores and gills, 2nd pair \ inch anterior to gills, 3rd, which 

 bear a few small branches, j inch behind gills. Rhinophores per- 

 foliated and retractile (though not readily so) into pockets, the tips 

 of which stand up to form a tube, so that only the perfoliate part of 

 the rhinophore is ever visible. Just postero-laterally to the rhino- 

 phores commences a peculiar membranous expansion of the head. 

 This membrane is undulated at the margin, and bears a row of 

 branched projections like tassels. These are tipped with bright 

 yellow, and in this, as in their fonn, they resemble a further develop- 

 ment of the branches of the dorsal papillae. The apparatus is mobile 

 and sensitive to touch. The colour of the animal is a red orange, 

 almost vermilion. Under the lens this does not appear homogeneous, 

 but as a yellow orange ground colour with dark red specks, and larger 

 spots of vermilion. The colour is deepest dorsally. The margins of 

 the root, which are spread out as an adherent membrane over the 

 substratum, are colourless, with yellow spots and darker specks of 

 brown. The body is very soft and translucent. The small specimen 

 was very much paler and yellower in colour, the dorsal papillae being 

 bright yellow, as were the tassels of the head-membrane and the ridge 

 of the tail. The big specimen was directly placed in a mixture of 

 alcohol and formol, and contracted very much. The smaller, killed in 

 glacial acetic acid, is comparatively little changed, but the head- 

 membrane is no longer distinct as such. In life it projected freely for 

 at least a \ inch in the big specimen. 



