114 



Lymneus pinguis. — Shell oval, rather ventricose, pale, dirty 

 yellowish ; whorls nearly four, rapidly diminishing to the apex, 

 which is dull fulvous ; suture moderate ; spire rather more than 

 half the length of the aperture; aperture large; labrum with the 

 inner margin a little thickened. 



Total length eleven-twentieths of an inch; aperture rather more 

 than seven-twentieths ; .breadth seven-twentieths. 



Proportionally shorter and much more dilated than other species 

 of the country, with the exception of L. macrostomus, nob., from 

 which it is readily distinguished. It inhabits the Delaware and 

 Schuylkill rivers near Philadelphia, in company with L. catasco- 

 pium, nob. 



Lymneus galbanus. — Shell subovate; whorls nearly five, 

 very convex; suture very deeply impressed; apex acute; body 

 whorl a little flattened in the middle ; aperture not dilated ; colu- 

 mella with the sinus of the fold very obvious. 



Length three-tenths of an inch : aperture rather more than half 

 the whole length. 



For this shell I am indebted to Mr. Nuttall, who obtained it in 

 a marl pit near Franklin, New Jersey. He considers it fossil, as 

 well as numerous specimens of Planorhls campanulafus, Valvata 

 tricarinata, and Phyi>a heterostropha, found with it. I have never 

 seen a recent specimen, but the present corresponds with some in- 

 dividuals belonging to the Philadelphia Museum, also said to be 

 fossil. 



PiiYSA ANCILLARIA. — Shell heterostrophe, subglobose, pale yel- 

 lowish; whorls rather more than four, very rapidly attenuated ; 

 spire truncated, hardly elevated beyond the general curve of the 

 surface; suture not impressed; aperture but little shorter than 

 the shell, dilated ; labrum a little thickened on the inner margin. 



Length more than one-half of an inch. 



The spire of this species is unusually short, truncated at tip 

 like the Paludina decisa, nob. ; and the suture is so inconspicu- 

 ous as to give rise to the name which I have chosen for it. My 

 brother, B. Say, obtained it in the Delaware river near Easton, 

 and Mr. Jessup collected numerous specimens in the Connecticut 

 river, above Hartford. It may be distinguished from P. hetero- 

 stropha, nob., by the shorter and truncated spire, inconspicuous 



