54 



LAND AND FRESH- WATER SHELLS OF N. A. [PART HI 



Fig. 108. 



Paludina coarc- 



tata. 



Alabama. E. Foreman, M. D. Cabinet of Dr. Foit-- 

 man. Diam. .50, lengtli .98 incli. 



• This species, of which a single specimen only was re- 

 ceived, diiFers from all of the genus which has come un- 

 der my notice. It is remarkable for its compressed form, 

 the body whirl being quite flattened. The apex is eroded, 

 which prevents the number of whirls being ascertained : 

 there appear to be five. The aperture is less round than 

 usual in this genus, and may be rather more than half 

 the length of the shell. {Lea.) 



Fig. 109. 



Paludina exilis. 



Paludina exilis, Anthony (/. 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, 

 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, 1^^ inch; breadth, ^ inch. 

 Ilab. — Mississippi. My Cab. ; Cab. H. Cuming, Lou- 

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

 N. Y. ; Smithsonian collection. 



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

 cies ;' Paludina suhsolida, nob., is more ponderous, more 

 globose, and has a larger aperture ; no other speciep 

 approaches it in general appearance ; the whirls of this 

 species taper more rapidly to an acute apex than in 

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

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



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

 spire obtusely elevated and composed of six convex g'hirls, which 

 are strongly striate or subcariuate ; sutures very distinct, and the upper 

 part of each whirl being flattened renders it more conspicuous ; aperture 

 broad-ovate, about half the length of the shell, livid 

 within ; columella slightly rounded and callous de- 

 posit small ; umbilicus none. 



Length, 1| inch ; breadth, f inch. 

 Hah.— South. Carolina. My Cab. ; Cab. H. Cuming, 

 London; A. N. S., Philadelphia ; Smithsonian collec- 

 tion, Washington, D. C. 



0()S. — In general form not unlike our western P. 

 Integra, Say, from which it diflers, however, by its re- 

 volving, raised strife and by its carinse, which are also 

 well developed ; the lines of growth are very strong, 

 ?.ludina lima. and decussating with the striae give the surface a beau- 



Fig. 110. 



