RISSOIDiB. 65 



Paludina incrassata, Lea. — Shell smooth, elliptical, rather thin, im- 

 perforate, dark horn color ; sutures somewhat impressed ; whirls 

 somewhat convex ; columella thickened above ; aper- 

 ture rather round, small, within bluish. Fig. 129. 



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

 man. Diam. .52, length . . . inch. 



Rather more than the first whirl only of the speci- 

 men before me is perfect, and I would not have pro- 

 posed it for a new species, but that this part differs 



from any whicli has come under my notice. The 



11 ii • i i? iT_ 1 ,1 • Paludina in- 



callus on the superior part of the columella is very crassata 



like that we find in the genus AncAilosn. The aper- 

 ture is smaller than usual in this genus. The upper whirls being 

 decollate, neither their number nor the form of the spire can be 

 given. (Lett.) 



Paludina incrassata, Lea, Tr. Am. Phil. Soc. IX, 30 (1844); Obs. 

 IV, 30 ; Proc. II, 243 (1842). 



The figure given above (Fig. 129) is taken from Mr. Lea's original 

 specimen. I have not seen others. 



Paludina thermalis, Linn., is quoted by Philippi from the United States, 

 Turbo tninutus, Say, being given as synonym (Arch. f. Nat. 1844, 28). 



Fossil Species of Viviparid^. 



Dr. Meek furnishes the following list of fossil American Viviparae, most 

 yf which were first described as Paludinae: — 



Vivipara veUista, Meek & Hatden Phila. Proc. 1860, 43 ; 1856, 121. 

 Vivipara leaii, « " 1860, 184 ; 1856, 121. 



Vivipara retusa, " " 1860, 185 ; 1856, 122. 



Vivipara conradi, « " 1860, 185 ; 1856, 122. 



Paludina pecidiaris, " " 1856, 122. 



Vivipara trochiformis, " " 1860, 185 ; 1856, 122. 



Vivipara leidyi, « " 1856, 123. 



Vivipara raynoldsana, " " 1861, 446. 



Vivipara nebrascensis {Paludina midtilineata, Meek & Hayden, Phila. 



Proc. 1856, 120) ; 1860, 430. 

 Vivipara glabra, H. C. Lea, teste Conead, Proc. Phila. A. N. S. 1862, 567. 



Family RISSOIDJE. 



Lingual teetli 3, 1, 3 ; the rows being more tnansverse and 

 less arcuated than in the Littorinidse. Ehachidian tooth 

 broader than long, and armed with basal denticles (so called 



