LIOPLAX. 



59 



Fig. 120. 



elevated ridge below the carina on the body whirl. 

 The revolving stritB are sometimes very strongly 

 marked. 



The opercnlum, which in the young 

 shell is subspiral, in its later growth is 

 concentric as in the other species of Vi- 

 viparidse. 



I have received specimens from Ohio, 

 Indiana, Kentucky, Pennsylvania, and 

 New Jersey. 



Faludina suJculosa, Menke, I. c, appears to me to be this 

 species. I have seen no authentic specimen. Ilis description 

 is as follows : — 



PaJudina sulculosn. — Shell ovate-conoid, apex deroded ; imperforate, tliiu, 

 decussately striated, transversely lightly sulcated ; green ; whirls 4, angu- 

 lated on the spire ; suture deep ; aperture ovate ; lip simple. Length 4h, 

 breadth 3 lines. 



Ohio River at Cincinnati. Bescke. (^Menke.^ 



Paludina bicarin ata, Foi'iQz and Michaud, is certainly this 

 species, as shown by their description and the copy of the outline 

 of their figure given below. 



Fig. 122. 



Paludina bicarinota, Pot. et Mich. (1. c.) not Say. — Shell oval, ven- 

 trifose, brown or greenish, covered with numerous trans- 

 verse ridges, two of which are more developed on the last 

 whirl, the other whirls having but one medial carina; spire 

 comprised of three or four convex whirls, of which the first 

 are usually truncate ; aperture ovoid ; peristome simple. 

 Length 12-15, breadth of last whirl 10-12 mill. 



Mr. Say and Ch. des Moulins have both given the same 

 name to two different shells belonging to this genus, conse- 

 quently it becomes necessary, in order to avoid confusion, to change that 

 of Des Moulins, being posterior to Mr. Say's. Moreover, M. des Moulins' 

 shell having three carinfe, will be better designated by the name tricarinata, 

 adopted in this catalogue. 



Delaware River, N. America. (Potiez ct Michaud.) 



I give also an outline of Wood's figure (Fig. 123) Fig- 123. 

 of decisa, of which no description is given, though it 

 is specified as "tawny Delaware." It is evidently 

 Lioplax suhcarinata. 



In addition to the above fac-similes I have given 

 one of Say's figures in Nicholson's Encyclopedia (Fig. 

 117.) 



