246 MR. W. HARPER PEASE ON NEW MOLLUSCA. [June 11, 



strongly dilated outwards, ear-shaped, obliquely truncate and grooved; 

 anterior of about the same size, rather more dilated ; the whole upper 

 surface is beautifully variegated with different shades of white, green, 

 olive brown, and sometimes blotched with rusty brown ; locomotive 

 disk pale greenish grey, closely and finely dotted with opake white 

 and pale olive. 



Hub. Tahiti. Quite common under stones in httoral zone. Their 

 motion is vivacious. They glide along by the middle and two lateral 

 portions of the foot alternately. 



This species approaches D. olivacea of the Sandwich Islands. 



LOBIGER ? 



Animal elongate ; the tail, margins of the foot, tentacles and centre 

 of natatory appendages beneath papillose ; anterior portion of the 

 body covered with a large Bulla-shaped shell, which is perforated at 

 the apex for the passage of water or excrement, and covered with a 

 thin greenish membrane ; tail long, arched, gradually tapering ; ten- 

 tacles four, auriform, subconvolute, somewhat dilated and truncated; 

 eyes immersed behind the dorsal pair ; natatory appendages thin, 

 oblong, elongate, anterior pair somewhat less than the whole length 

 of the animal, posterior a little shorter than the anterior, widest at 

 their outer halves, and their sides deeply incised, giving them a leaf- 

 like appearance ; locomotive disk like Aplysia. Colour pale pea-green, 

 tips of the tentacles tinged with yellow, a dusky marginal band along 

 the edge of the body ; the upper surface of the natatory lobes are 

 greenish centrally, fading into yellowish pink towards the margins, 

 which are white ; the lower surface is of the same colour, but brighter, 

 and the margins dusky. 



Station, among sea- weed on sandy bottom, in sheltered places. 

 When disturbed, they cast off all their lobes, which retain their vi- 

 tality for several hours. 



The above species I place provisionally under this genus until 

 more fully examined. It differs, however, in the shape of its shell, 

 and the number and shape of its tentacles. 



LOPHOCERCUS VIRIDIS. 



Body oval or ovate ; dorsal region elevated ; tentacles well deve- 

 loped, grooved and truncated ; eyes immersed immediately behind 

 the tentacles ; lateral lobes regular in shape, outhne of the edges 

 convex, not meeting ; foot linear, adapted for clasping sea-weed ; the 

 whole upper surface garnished with more or less numerous, cirri- 

 gerous appendages. Colour grass-green, mottled with darker ; some 

 are minutely dotted with brown, others with a few blue dots, mar- 

 gined with black rings along the edge of the lateral lobes and on the 

 neck. 



Shell thin, fragile, white, ovate, striated obliquely, convolute ; outer 

 lip separate from the apex, overlaps the inner posteriorly, and pro- 

 duced in a tubular form. 



Station, on sandy bottom, among sea-weed, in shallow water. 

 When handled, it discharges a white viscid fluid. 



