VITRINID^E. 135 



Genus TRIGONOCHLAMYS, Bottger, 1881. 



Animal limaciform, with two dorsal and two lateral grooves 

 directed from the mantle towards the head ; shield behind the 

 middle of the bod} r , very small, attached all around, granular ; 

 anal and respiratory orifices behind the right margin of the shield ; 

 tail short, compressed, carinated, without mucous pore; jaw 

 without ribs, teeth like Testacella. No internal shell ? Caucasus. 



Subgenus PSEUDOMILAX, Bottger, 1881. 



Differs in its shield being free in front and on the right side. 

 No internal shell ? . Caucasus, etc. 



** With mucous pore. 



Genus DAMAYANTIA, Issel, 1874. 



Animal limacifcrm ; mantle a visceral sac, anterior, convex 

 behind, well separated from the foot ; tail with a mucous pore ; 

 respiratory orifice on the right side, anterior to the mantle ; sole 

 longitudinally bisulcate ; jaw unknown. No internal shell? 



Described from a single specimen. Appears to be related to 

 Parmarion. 



Genus LACONIA, Gray, 1855. 



Shell subglobose, entirely and permanently covered by a thin 

 expansion of the mantle ; spire of few whorls, the last very large ; 

 aperture very large, lunate. 



Animal with subglobose body; mantle edged, produced in 

 front, forming a broad collar, tail with a mucous pore. 



The habitat of the single species is unknown, and the mollusk 

 and its shell are only known by a figure in Ferussac's " Histoire 

 nat. des Moll." 



Genus MARIAELLA, Gray, 1855. 



Shell internal, entirely concealed by the mantle, rudimentary, 

 oval, thickened, calcareous, with epidermis, nucleus scarcely 

 spiral, upper surface slightly convex. Young shells are concave 

 below, adults are much thickened and flattened below. 



Aniinal limaciform, subcylindrical, truncated behind, with a 

 linear mucous pore ; mantle large, anterior, concealing the shell ; 

 locomotive disk distinct. Jaw smooth, with a median projec- 



