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 KEL., Ann. Mag. N. H., (3), iii, p. 

 495; Journ. Ceyl. Branch Roy. Asiatic Soc., iii, p. Ill, 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 proboscidifornu 

 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 PSE., P. Z. S., 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- 



