VIVIPARA. 



31 



a form with three revolving raised lines or keels, from Pulaski 

 County, Arkansas. 



Paludina exilis, Anthony, (1. c.) — Shell turreted, smooth, rather thick ; 

 color light apple-green ; spire elevated, composed of about seven 

 volutions ; suture well marked ; aperture small, broad- 

 ovate, livid within ; body whirl distinctly angulated, pig, 52, 

 subumbilicate, and with very distinct lines of growth ; 

 columella well rounded and curved with a callous de- 

 posit, connecting perfectly with the outer lip, thus 

 forming a continuous rim. 



Length, l^^ inch; breadth, | inch. 



Hab. — Mississippi. My Cab. ; Cab. H. Cuming, Lon- 

 don ; A. N. S. Philadelphia ; State collection, Albany, 

 N. Y. ; Smithsonian collection. 



Obs. — One of the most slender of our American spe- 

 cies ; Paludina subsolida, nob., is more ponderous, more 

 globose, and has a larger aperture ; no other species 

 approaches it in general appearance ; the whirls of this Paludina exilis. 

 species taper more rapidly to an acute apex than in 

 most of the species ; compared with P. iniegra, Say, it is more slender, 

 more solid, and the aperture is much smaller. (Anthony.) 



Paludina lima, Anthony, (1. c.) — Shell ovate, rather thin, dark green; 

 spire obtusely elevated and composed of six convex whirls, which 

 are strongly striate or subcarinate ; 

 sutures very distinct, and the upper Yig. 54. 



part of each whirl being flattened ren- 

 ders it more conspicuous ; aperture 

 broad-ovate, about half the length of 

 the shell, livid within ; columella 

 slightly rounded and callous deposit 

 small ; umbilicus none. 



Length, 1^ inch ; breadth, ^ inch. 

 Hab. — South Carolina. My Cab. ; 

 Cab. H. Cuming, Loudon ; A. N. S., 

 Philadelphia ; Smithsonian collection, Palmltna lima. 

 Washington, D. C. 

 Obs. — In general form not unlike our western P. integra, Say, from 

 which it differs, however, by its revolving, raised stria3 and by its carinse, 

 which are also well developed ; the lines of growth are very strong, and 

 decussating with the striae give the surface a beautifully rough appearance, 

 which suggests its specific name. It is really one of our handsomest 

 species, and so unlike all others that no American species can readily be 

 mistaken for it. In most specimens the body whirl is very strongly cari- 

 nate about the middle, and the outer lip is considerably produced as in 

 P. subsolida, nob. (Anthony.) 



Fig. 53. 



Paludina lima. 



