THE NAUTILUS. 43 



Paludina lima Anth., as his description does not fit it, being 

 partly drawn from the Florida species, partly compiled from 

 Anthony. 



The shell has a rather short spire and large aperture, it varies 

 on different parts of the same specimen, and in different speci- 

 mens from dark citrine to blackish brown. The interior is 

 chocolate, chestnut-brown or dark indian-red ; the invariably dark 

 color being highly characteristic. The surface has unequal, 

 minute, spiral strise. The last whorl is somewhat compressed 

 below the narrow subsutural shoulder. Columella rather heavy, 

 nearly white. A large specimen measures, length 34.6, diam. 

 22.3, aperture 19.8 mm., 4 whorls remaining. 



So far as known, this species is restricted to the St. Johns 

 River and tributary creeks, in Florida. Mr. Johnson and the 

 writer dredged it in Lake County. It is one of the most distinct 

 species, owing to its color. 



Campeloma limum (Anth.) is a more slender, green species 

 with a smaller mouth, bluish within, and a more or less dis- 

 tinctly subangular periphery. Melantho decampi W. G. Binney 

 is a synonym of C. limum. 



THE RAFINESQUE-POULSOH UNIOS. 



BY BRYANT WALKER. 



In publishing the complete list of the Rafinesquean Unios in 

 the Poulson collection with their modern equivalents, Mr. 

 Vanatta has rendered a distinct service to all students of the 

 American Naiades. Now, for the first time, we, to whom the 

 specimens are inaccessible, are informed exactly as to which of 

 the species familiar to us under Simpsonian designations are 

 represented in that famous collection and their names as iden- 

 tified by Rafinesque himself. 



While, with a single exception, it is not claimed that these 

 are the original types of Rafinesque' s species, and it is explicitly 

 stated that the ultimate recognition of any of Rafinesque' s 

 species "depends upon whether it could be identified by de- 

 scriptions published prior to any other recognizable name fo r 



