POMATIOPSIS. 



93 



POMATIOPSIS, Tryon. 



Jaws like those of Amnicola, tliougli smaller. Lingu'al mem- 

 brane with numerous rows of 3, 1, 3 teeth ; centrals small, 

 broader at base, cusp recurved and tridentate, base with two 

 obtuse denticles ; laterals longer than broad, cusp recurved and 

 denticulate, the inner lateral much broader than the two outer 

 ones. 



Fig. 1S6. 



Lingual dentition of Pomatiopsis lapidaria. — [Stimpson.] 



Fig. 187. 



Tentacles short, subulate, pointed, rostrum large, longer than 

 the tentacles. Foot broad. Verge very large, 

 flattened, broad, convoluted in a spiral coil 

 of one and a half turns. Ova capsules — ? 

 Shell small, thin, smooth, long, subumbili- 

 cate. Spire turreted. Aperture ovate, peri- 

 treme reflected. Operculum corneous. 



Eastern North America. 



Animal of P. lapidaria. 



Terrestrial. enlarged. 



Pomatiopsis lapidaria, Sat. — Shell turreted, sub- Fig. 188. 

 umbilicate, with six volutions, wliicli are obsoletely wrinkled . 



across. Sutui'e impressed. Aperture longitudinally ovate- P\ 



orbicular, operculated, rather more than one-third of the \A 



length of the shell. 



Length about one-fifth of an inch. Collection of the Aca- 

 demy of Natural Sciences. 



Inhabitant not so long as the shell, pale ; head elongated into a rostrum 

 as long as the tentaeula, and emarginate at tip; tentacula two, filiform, 

 acuminated at tip, short; eyes prominent, situated at the external or 



Pomatiopsis 

 lajndaria. 



