FAMILY AUMCULACEA. 125 



and the eyes separate from the tentacles, simply as specks in the 

 skin-surface, so to speak, of the head, presenting a transition in 

 these respects to Acme and Cyclostoma, which are operculated air- 

 breathers. The upper tentacles are short, thick, and rather approxi- 

 mated at the base ; the lower tentacles are almost obsolete. 



The particulars in which Carychium and Conovulus differ, are 

 important. Carychium, in whatever country it has been observed, 

 is a minute mollusk, carrying a transparent glassy shell toothed in 

 the aperture somewhat after the manner of Vertigo, and Hving in 

 inland places among moss or dead leaves wet with fresh water, or 

 in crevices of the stems of freshwater plants. It appears through- 

 out Europe, in Siberia, in North Africa, in the western sub-Hima- 

 layan mountains of India, and in the United States ; yet it is doubt- 

 ful whether more than ten species are known, including four of 

 a particular globose form, inhabiting the subterranean caverns 

 of Carniola, Austria, of which as many as thirteen species have 

 been made by M. Bourguignat under the title of Zospeum. 

 Conovulus is of much larger dimensions, and has a solid epidermis- 

 covered shell of the characteristic exotic type already described. 

 Conovulus is not found inland in the vicinity of fresh water. It in- 

 habits mud-banks and sand-hills in places washed with brackish 

 water, or even within range of the sea, especially in saline marshes. 

 Mr. Cuming collected Conovuli, almost identical with the British 

 species, at Lima, in saltwater ponds at least three miles from the 

 sea, the intermediate land being chiefly salt, with the scantiest pos- 

 sible vegetation. 



The British genera of Auriculacea are : — 



1. Carychium. Animal pale yellowish, strongly bilobed in front, 



head produced into a ringed muzzle, eyes at the hinder base 

 of the tentacles. Shell conically turbinated, of five to five 

 and a half glassy whorls, one-toothed at the three angles of 

 the aperture. 



2. Conovulus. Animal violaceous yellow or grey, faintly bi- 



lobed in front, head produced into a ringed muzzle, eyes at 

 the inner hinder base of the tentacles. Shell of six to seven 

 fusiformly convoluted whorls, plaited and toothed on the colu- 

 mella, and sometimes toothed within the lip. 



