THE FAMILY NAIADES. 



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OVAL. 



Unio capillus. Say, Transylvania 



Journal, Vol. V. 

 U. lapillus. Say, Am. Conch. No. 5, 

 Con. 



•parvus. Bar. Eat. 

 Unio parvus. Con. 



*glans.t Lea. 



*divaricatus. Lea. 



*faba. D'Orb. 



*Burroughianus. Lea. D^Orh. 



*cliscus. Lea. 



"simus. Lea. 



*corrugatu3. Lam. 



Mya corrugata. Midler. Chem. 



Gmel. TVood. Dill. 

 Mya rugosa. Gmel. Wood. Dill. 



OVAL. 



Mya nodosa? Gmel. Wood. Dill. 

 Mya spuria. Gmel. 1 Wood. 

 Unio spuria. Lam. 

 Unio triradiata. In " Museum" at 

 Paris. 



"Niloticus. Fer. Caill. 

 Mya pictorura. Forkael.X 



*Egyptiacus.§ Caill. Fer. 



OBLONG. 



*brevidens. Lea. 



tetralasmus. Say. 



*caiTiptodon.|| Say. 

 Unio declivis.% Con, 



*obesus.ff Lea. 

 *Hopetonensis. Lea. 

 *Roanokensis. Lea. 



December number (1831) of the Transylvania Journal, and subsequently in the " Amer. Conch." No. 5, (Aug. 

 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. 



t Mr Say doubts if the glans be not the same with parvus. I do not see how there can be any difficulty 

 in distinguishing them. The glans 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 i^||^ 

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

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

 differ essentially. 



\ On the authority of Ferussac. 



§ The specimen of this species which I received from M. Caillaud, the traveller, is so much like Niloticus, 

 that I certainly would not myself have separated it. 



II This fine shell, as well as the preceding one, both of which are Mr Say's, seem to have been overlooked 

 in the formation of his catalogue. They are described in his Amer. Conchology. I have never seen the shell 

 he calls tetralasmus, — they may possibly prove to be the same. 



II The shell in the Academy of Nat. Sci., described and figured by Mr Conrad in his "Monography," page 

 45, as declivis. Say, I consider to be a middle aged camptodon, Say. This, however, is not the opinion of all 

 our conchologists. 



tt Ferussac believes that this is Carolinianus of Bosc. Not having seen the specimen described by Bosc, 

 nor having access to his description, I am unable to decide. Tlie fact, however, of Bosc's having visited Caro- 

 lina some forty years since, renders it highly probable to be so. Ferussac gives his trapezium as a synonym 

 to Carolinianus. In my table of the Uniones made in 1829, I considered Carolinianus as the complanatus : 

 in which I was most likely wrong. 



