U N I 0. 



31 



OVAL. 



*creperus. Lea. Ohenu. 



*glaber. Lea. Ohenu. 



^fabalis. 1 Lea. Ohenu. 



Unio capillus. Say, Transylvania 



Journal, vol. v. 

 Unio lap>illus. Say, Am. Conch. No. 

 5. Oon. 



*paulus. Lea. Ohenu. 



*pusillus. Lea. Ohenu. 



*parvus. Bar. Eat. Con. Phili. 

 Kust. 



*Haleianus. Lea. Ohenu. 



*nigerrimus. Lea. 



*minor. Lea. 



*glans. 2 Lea. Kust. Ohenu. 



*nux. Lea. 



Brumby anus. L 



ea. 



OVAL. 



*msestus. Lea. Ohenu. 



*pullus. Oon. 



*divaricatus. Lea. 



*Petterianus ? Kust. 3 

 Unio carneus. Kust. 



*faba. L'Orb. 



*ineptus. Lea. 



*Burroughianus. Lea. D' Orb. 



*discus. 4 Lea. Ohenu. 



Unio Panacoensis. V. d. Buseh. 

 Phili. 



*simus. Lea. Ohenu. 

 multidentatus. Phili. 



*Niloticus. Caill. Per. JDesh. 

 Menke. Potier. 

 Mya pictorum. Forkael. 5 

 Unio pumilis. Zeig. 

 Unio Pareyssi. V. d. Busch. 



1 Say and Conrad both, in their catalogues, give precedence to lapillus. Fabalis is in my Memoir read before 

 the Am. Philos. Soc, May 7, 1830, and inserted in the Transactions; capillus was first inserted in the December 

 number (1831) of the Transylvania Journal, and subsequently in the Amer. Conch., No. 5 (August, 1832), under 

 the name of lapillus. Mr. Say does not mention why he changed the name on redescription. I should prefer the 

 first, as a more descriptive name, were I to choose between the two. 



2 Mr. Say doubts if the glans be not the same with parvus. I do not see how there can be any difliculty in 

 distinguishing them. The"?cms is a much heavier shell, and the nacre of all the specimens I have seen is more or 

 less purple, while that of parvus is always, I believe, white. Among many hundred specimens which have come 

 under my notice, I have never seen one of any other color. The texture of the nacre is also totally different, the 

 latter being more pearly than any other of our Uniones. In the epidermis and beaks they also differ essentially. 



3 U. Petterianus and U. carneus were sent to me by Dr. Vandenbusch, of Bremen, as distinct species. I 

 believe the latter to be the old of the former, thrown out of its normal form by much erosion at the beaks. They 

 are from Montenegro, and may prove to be only a variety of Unio Batavus. See Krister's edition of Martini, PI. 

 26, Fig. 4. 



4 Unio discus is found in Moctizuma River, Central America, and occurs white, and beautifully salmon color, 

 as well as purple. 



5 Fide Ferussac. 



