304 HELICID^. 



Genus CYLmDRELLA, Pfeiffer. 



GENERIC CHARACTERS. 



Animal small and shoi-t compared with the shell, in 

 general like that of Helix ; tentacles four, the superior 

 of medium length, the inferior quite short. Motions 

 sluggish ; the shell drags horizontally, nearly in the line 

 of motion. 



Shell elongated, cylindrical, or fusiform, composed 

 of numerous whorls, the last of which is usually disjoined 

 from the preceding, and partially uncoiled ; aperture 

 with a continuous, revolute lip, circular or polygonal; 

 its plane nearly parallel with that of the axis of the 

 shell. 



Geographical Distribution. As far as we know, 

 this genus is confined to the islands and shores of the 

 Gulf of Mexico. There are abundant species in Cuba 

 and Jamaica, and, doubtless, on other islands. A few 

 have been found in Texas and Mexico, and three species, 

 as we regard them, are found in East Florida, one of 

 which, and probably all, is found on the island of Cuba. 

 A single species has been named as coming from the Phi- 

 lippine Islands ; but we apprehend there may have been 

 some mistake in this, either as to the locality or as to 

 the genus ; possibly, it might have been a Truncatella. 



Remarks. The group of shells here designated was 



