264 APPENDIX. 



Vol. iii. p. 125. Rissoa vitrea. 



We have taken this animal alive in fifteen fathoms water, off 

 Oban. It is entirely of a translucent white, except the rather 

 long and somewhat bilobed muzzle, which, owing to the dental 

 apparatus within, appears tawny. The tentacles are subulate, 

 somewhat flattened, rather, but not very long, obtuse but not 

 clavate at their tips. The eyes are small, and placed at their 

 bases, superiorly and centrally. When the animal crawls, the 

 eyes are usually concealed under the transparent margin of the 

 shell. The foot is rather broad, oblong, somewhat spreading 

 and bilobed in front, with broad obtuse auricles ; behind, it is 

 rather short, flattened, and terminally rounded. The opercular 

 lobe is very short, rounded, and quite simple, there being no 

 cirrhus. The operculum itself is rounded, thin, and of a very 

 pale horn-colour. 



Mr. Clark has also met with and described this rare animal. 

 His account of it is substantially the same ; he notices, however, 

 setae on the ends of the tentacles, and describes the operculum as 

 clear white. 



Vol. iii. p. 127. Rissoa proxima. 



Mr. Clark has been so fortunate as to take this mollusk alive, 

 in fifteen fathoms water, off Exeter. He states that it is of a 

 brilliant subhyaline white hue, specked with opaque white flakes, 

 and tinged with claret red on the neck. The mantle (as in the 

 last species) is even. The muzzle is short, subcylindrical, and 

 obtuse. The tentacula are flat, strong, rather short, smooth, 

 minutely claviform at the tips, which are each clothed with six 

 comparatively long, intensely aciculate setae. The eyes are un- 

 usually large, black, and placed on bulgings at the external bases 

 of the tentacula. The foot is large, fleshy, grooved in front, 

 deeply indented in the centre, and produced at the angles into 

 large, long, pointed auricles. The tail is divided into two long 

 distinct streamers. Above the bifurcation is a small opercular 

 lobe, without any filament. The operculum is white, horny, sub- 

 oval, and of four or five whorls. 



