68 CONCHOLOGIA CESTRICA. 



P. lata, TRYON, Contin. F. W. Moll. U. S. 

 p.iata. Shell, very fragile, light horn color, waxy, 

 irregularly striate ; spire moderately elevated ; 

 whorls convex ; apex acute ; suture well im- 

 pressed ; body inflated ; aperture rather large ; 

 columellar lip turned to the right, very narrow, 

 distinctly folded. H. 10.5, W. 7, mill. 



Station, Juniata River, Hollidaysburg, Penn- 

 sylvania. 



OBS. This species not having fallen under our ob- 

 servation, the figure and description have been taken 

 from the recent admirable continuation of Haldeman's 

 Monograph of the Fresh Water Univalve Mollusca, by 

 G. W. Tryon, Jr., who observes that " this species has 

 very much the form of P. heterostropha, Say, but is 

 rather more ventricose, much thinner, and the surface 

 exhibits a peculiar, glimmering lustre." 



Genus BULINUS, ADANSON, 1757. 



Animal of Jtuiinus. Shell, sinistral, elongated, polished, 

 Fig, 134, thin, acuminate ; aperture narrow, pro- 



duced anteriorly. 



Animal, tentacles filiform, seta- 

 ceous ; mantle simple, not fringed, and 

 not reflected over the shell, as in Physa. 



B. hypnorum, LINN. 



Physa hypnorum, Linn., Syst. Nat, 1758. 



ji. hifpnorum. Shell, oblong, fragile, diaphanous ; whorls 

 Pig. 135. 6; spire acute ; aperture not dilated, atten- 

 uated above, half the length of the shell ; 

 columella narrowed at the base. H. 17, 

 W. 7, mill. 



Station, in flowing streams, and stagnant 

 pools. New Garden, Chester County; rare. 



