44 



MARGARITANA. 





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ARCUATE. 



C/W0 elongata. Lam. Mich. Bouil. 



Nils. Puton. Potier. Pup. 



Merm. 

 Unio ater. Nils. Rossm. 

 Unio sinuata. Pfeif. 

 Unio Roissyi. Mich. Pesh. 

 Unio margaritiferus. Retz. 



Cuv. Pray). Rose. Turt. 



Rossm. 



G-raells. 



Rose. 



Pfeif. 



Gaert- 



Pup- 



ner. 1 MenJce. 



Bouil. Alder. 

 Unio margaritifer. 

 Unio rivalis. Zeig. 

 Unio Carolinian us. 2 

 Alas, margaritiferum. Fhm. Rroion 



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ARCUATE. 



Alas, margaritiferus. Thompson. 



Forbes. 

 Alas, elongatus. Thompson. 

 Alas, arcuata. Rar. Gould. Adams. 



3Iigh. Linsl. Pekay. 

 Alas, falcata. Gould. 



*Holstonia. Lea. 

 *fabula. Lea. 



The following species are unknown to me : — 



Alasmodonta Tripolitana. Per. 

 Alasmodonta incurva. Per. 

 Margaritana Etowaensis. Con. 



1 Fide Menke. 



2 I have heen, and am still, perplexed ahout this species of Bosc. M. Ferussac considers it the same with 

 Unio obesus (nobis), and I so stated it in my last edition. Recently, I have had access to Bosc's description and figure 

 (Hist. Nat. des Coquilles), which agree better with Margaritana margarilifera than any other species; and he 

 refers to the figure of it in Ency. Meih. 



