UNIO. 



43 



1 



y. 



I 



OVAL. 

 *flavescens. 1 Lea. 



*pictus. Lea. Hun. 

 *fucatus. Lea, 

 *pallescens. Lea. 

 *perpastus. Lea. 



Mortonicus. Reeve. 

 *Tennesseensis. Lea. Chenu. 



*interruptus. Lea. Chenu. Han. 

 Unio tseniatus. Con. Han. 

 Unio latiradiatus. Con. 



*Menkianus. a Lea. Chenu. Han. 

 *bracteatus. Gould. 

 *Lindsleyi. Lea. 

 *punctatus. Lea. 

 *Stonensis. Lea. 

 *venustus. Lea. Chenu. 

 'exiguus. Lea. Chenu. Han. 



-x- 



OVAL. 

 *Kutersvillcnsis. Lea. 



*Topekaensis. Lea. 

 *planicostatus. Lea. 

 *spatulatus. Lea. 

 *Anthonyi. Lea. 



*ligamentinug. Lam? Kust. 



Unio crassus. Say. Bar.* Hild. 

 Kirtl. Han. 



Unio ellipticus. Bar. Hild. 



Unio carinatus. Bar. 

 Mya elliptica. Eat. 

 Afya carinata. Eat. 

 Mya crassa. Eat. 

 Mya fjravis. Wood. 



Unio fasciatus. Con? Kust. 



*exactus. Lea. 

 *purus. Lea. 

 *cognatus. Lea. 

 *Plantii. Lea. 



*orbiculatus. Hild. Kirtl. Han. 

 Unio abruptu3* Say. Desk. 

 Unio crassus. Con. 



1 This may be a variety of Greenii, Lea. 



2 Koch and Dunker described a fossil species (Menkei) in 183T: Beitr'drje zur Kenntniss, p. 58. My 

 species was described in the Trans. Am. Phil. Soc. 1836, and must therefore have precedence. 



3 Having recently had access to Retzius's work (1788), I find that he described a European Unio 

 under the name of crassus, which species had been admitted into our systems under the name of crassw- 

 SWIMS, Fer., I now restore it to its proper place under the name of eras.--'/.--. M r. Suy Described his crassus 

 as having "waves;" but his figure, inside view only, certainly is a species without "wavr-." 



Deshayes thinks that U. ligamentinus is analogous to U. multiradiatus, and probably a young Indi- 

 vidual of it. This is not likely to be the case, however. The species arc MTV dinVivnt. 



* Mr. Barnes made eleven varieties of crassus; most of which were, no doubt, distinct species; some 

 were plicate. 



6 Mr. Conrad thinks the crassus of Say isfasciafa of Rafiuesque. An examination of his description 

 ought to satisfy any one that the crassus of Say could not have been under the eye of the author when 

 he made his description of fasciata. 



6 The specimen figured by Say, in Amer. Conch. Xo. 2, is a female shell. The male shell is not abrupt 

 at the posterior margin. 



