cYLiciixnu:. 9 



Fam. CYLICIINMME. 



Teeth, central none, lateral 6. 6, the inner large and 

 hooked, the outer small and uniform, rarely wanting. 

 Head with the frontal disk depressed, sub-quadrate, 

 truncate in front, produced behind into broad, flattened, 

 recumbent, tentacular lobes, with the eyes immersed in 

 the front of their bases. Mantle with a posterior thick- 

 ened process or lobe. Foot shorter than the shell, trun- 

 cate in front. 



Operculum none. 



Shell external, spirally convoluted, more or less cylin- 

 drical, without coloured markings. 



In this group the cephalic disk is furnished with lateral 

 lobes, which are not folded and ear-like as in Aplustridte ; 

 the labial tentacles also are not developed as in that 

 family, and the foot is small and truncate behind, instead 

 of being large, expanded, and membranous. Their 

 habits are sluggish, and their progression very slow, the 

 locomotive disk not being well-developed. 



Genus CYLICHNA, Loven. 



Tentacular lobes connate, indistinct ; eyes sessile on 

 their front bases. Mantle with a thick, posterior lobe, 

 partially closing the aperture of the shell. 



Shell solid, cylindrical, involute; spire none, apex 

 obtuse, umbilicated ; aperture narrow and linear, as long 

 as the body-whorl ; inner lip callous, with a single, 

 anterior fold; outer lip straight, simple. 



