97 



gated shell, and will hardly be confounded with it. 

 The name Interruptus cannot be retained for this 

 shell, since, if Rafinesque's species be rejected, it 

 must be applied to the trapezoides of Lea, in right of 

 priority, as the latter was described by Say under 

 the name of interruptus. The largest specimen 

 measures 3| inches in length. 



UNIO SUBINFLATUS. 



Plate LIV.— Fig. 1. 



DESCRIPTION. 



Shell ovate-oblong, posterior side slightly ventri- 

 cose; ligament margin elevated, slightly ascending; 

 umbones very wide; beaks distant from the anterior 

 margin, not in the least prominent, decorticated; 

 anterior margin rounded, not very obtuse; umbonial 

 slope scarcely angulated; posterior extremity obtuse, 

 direct; epidermis reddish-brown and olivaceous, 

 smooth, with unequal green rays; within pale purple; 

 cardinal teeth robust, not very prominent, sulcated; 

 lateral teeth arcuate, rather thick. 



SYNONYME. 



U. complanatus, variety subinplatus, Nob. New Fresh 



Water Shells, Appendix, p. 5, pi. ix., fig. 2. 

 Cab. Ji. N. S., No. 20426. 



OBSERVATIONS. 



I found this species several years since in the 

 Savannah river, at Augusta, Georgia, and considered 



