OF CONCHOLOGY. 303 



Australia. The above is the most nearly allied to B. digitata 

 (A. Ad.) from which it differs in the number and character of its 

 branchial and tentacular processes, &c. 



As remarked by Mr. Adams, the animal lives on seaweed, for 

 which its foot is adapted, is active and occasionally swims by 

 rapid lateral undulations of its body. 



Placobranchus gracilis. Pease. Plate 21, fig. 1, a, b. 



Animal oblong, depressed, tapering posteriorly and truncate 

 behind. Head broad, cordiform in front. Tentacles tapering, 

 involute. Eyes black, on a slight prominence between the ten- 

 tacles. Veil cordiform in front and slightly auriculate. Color 

 cream yellow, with shades of a pale dove color, sides shaded with 

 light ochre yellow. Tlie posterior end margined with violet, also 

 the anterior edge of the head and veil. Tentacles annulated 

 with violet near their tips and a shade of the same color beneath. 

 The upper surface is closely ocellated with small, irregular sized, 

 olivaceous yellow round dots, with whitish irides. Along the 

 sides and on tlie front of the head the ocelli are larger, with 

 bluirfh green pupils, black and white rings. The lower surface 

 is bluish white and closely ocellated with irregular sized oliva- 

 ceous yellow pupils and white irides. Branchiae deep grass 

 green. 



Length, two inches. 



Habitat. Tahiti. 



Placobranchus variegatus, Pease. Plate 21, fig. 2, a,b. 



Animal smooth, elongate, oblong, truncate behind, sides nearly 

 parallel, and slightly tapering posteriorly. Head large, broad, 

 rounded and slightly emarginate in front. Tentacles large, 

 grooved and blunt. Eyes approximating on a prominent tuber- 

 cle, between the hinder bases of the tentacles. Veil well de- 

 veloped, rounded in front, auriculate, with a slight anterior 

 emargination. 



Color pale brownish grey, paler beneath. The upper part 

 covered with closely set ocelli ; those on the mantle have ochre 

 yellow pupils, and white irisis ; among them are interpersed a 

 few black dots and rings. Along the sides, the pupils of the 

 ocelli are rich yellow. The ocelli on the head have yellow pupils 

 and white irisis. Beneath the ocelli are much more remote, and 

 have black pupils. The branchiae are rich green. 



Length, tAVo and a half inches. 



Habitat. Island of Huaheine. 



