316 PYRAMIDELLIDiE. 



stated to be rounded and bilobed. Judging from the 

 delineation we should imagine the figured example to be 

 immature. 



The true position of the two following genera is doubt- 

 ful. Both appear to have relations, possibly only of 

 analogy, with Conovidus. In Truncatella both animal 

 and shell have many important points of resemblance with 

 Chemnitzia and its allies, though, at the same time, there 

 is an apparent affinity with Rissoa. In Otina, we have 

 a shell approaching that of Natlca, and scarcely distin- 

 guishable from that of Velutina, whilst the animal is very 

 distinct from either, and has, it seems to us, a near con- 

 nection with Truncatella. The curious Bissoa-Wke shells 

 placed by Philippi in the last-named genus, and consti- 

 tuted by Pfeiffer into a distinct group, under the name 

 of Paludinella, may constitute a link between them. 



TRUNCATELLA, Kisso. 



Shell turretcd, apex dextral, deciduous ; lower and 

 persistent portion cylindrical ; surface usually plicated 

 longitudinally. Aperture ovate, entire ; operculum corne- 

 ous, simple, not spiral. 



Animal with short diverging triangular tentacula, the 

 eyes placed centrally at their upper bases. Head bilobed, 

 more or less muzzle-shaped. Foot short, rounded at both 

 ends. 



This genus was constituted to receive certain shells 

 included by Draparnaud in Cyclostoma. Its animal has 

 been carefully examined by Lowe and by Philippi, Al- 



