218 OSCANIUS. 
inches broad. The young is of a lighter purple, and may be mis- 
taken for another species. (Kel.). 
Trincomalee, Ceylon, in deep water (Kelaart). 
Pleurobranchus purpureus Keu., Ann. Mag. N. H., (3), iii, p. 
495; Journ. Ceyl. Branch Roy. Asiatic Soc., iii, p. 111, for 1856— 
1858. 
O. VIOLACEUS Pease. 
Oval, convex above, and covered with crowded depressed gran- 
ules, with multiangular bases. Mantle rounded behind and deeply 
sinuated in front, and repand, rather thin and undulated along the 
lateral margins. Tentacles arising from the lateral anterior portion 
of the head, approximating at their bases, stout, large, truncated, 
slightly swollen, transversely laminated, grooved in front. Eyes 
sessile, conspicuous at their posterior bases. Mouth proboscidiform. 
Veil large, granose above, triangular, and grooved laterally. Bran- 
chial plume single, simple, pinnate, on the middle of the right side, 
free half of its length, along the middle of the plume two rows of 
alternate granules. Foot large, oval, reaching the margins of the 
mantle laterally and projecting a little posteriorly. Color above 
pale purplish, with much darker granules, which gives it a beauti- 
fully reticulated appearance; beneath paler than above; disk of the 
foot light purplish-grey. (Pse.). 
Sandwich Is. 
Pleurobranchus reticulatus Pse., P. Z. S., 1860, p. 25 (not of 
Rang.).—P. violaceus Psx., P. Z. 8., 1863, p. 510. 
O. GRANDIS Pease. PI. 45, fig. 1. 
Shell none. Animal oblong-oval, subpellucid, flaccid, depressly 
convex, covered with a network of impressed lines, the interspaces 
finely tuberculated. Mantle covering the head, deeply notched in 
front. Head small and narrow; oral veil moderately developed, 
subtriangular, sides biplicate. Tentacles smooth, stout, truncate, 
involute. Eyes very minute, scarcely visible without the aid of a 
lens, deeply immersed at the base of the tentacles. Foot large, thin, 
elongate oblong, convexly truncate and duplicate in front, rounded 
behind, when creeping projects far behind the mantle, generally 
much exposed from above, as well as the gill, Gill very large, the 
two rows of plumules folded against each other, each one consisting 
of twenty-six tripinnate plumules, disposed alternately, and tuber- 
