UNIO. 



19 



III. SUBGENUS UNIO. 



f TRIANGULAR. 



*Cumingii. Lea. 



gigas. Lea. 

 Lymnadia gigas. Swain. 



*Nicklinianus. Lea. 



*Boykinianus. Lea. Chenu. 



*inflatus. Lea. Kilst. 



Sympli. inflata. Lea, in Trans. Am. 



P. S. 

 TJnio Alabamensis. Con. 



*delphinus. Chrun. Lea. Kilst. 



*alatus. Say. Lam. Sivain. Bar. 



Hild. Menke. Adams. Kilst. 



Belcay. Potier. Deshayes. Con. 



Sow. 

 Mya alata. Wood. 

 Sympli. alata. Lea, Trans. Am. P. S. 

 Lymnadia alata. Soiv. 

 Metaptera alata. Stimpson. (Agass. 



MSS.) 



*superbus. Lea. 

 *kevissimus. Lea. 



TRIANGULAR. 



Sympli. Ixvissima. Lea, in Trans. 



Am. P. S. Eaton. 

 TJnio Isevissima. Deshayes. 



^gracilis. Barnes. Hild. Desh. 

 Adams. 

 Unio planus. Barnes. 

 TJnio fragilis. Sivain. Kilst. 

 Sympli. gracilis. Lea, in Trans. Am. 



P. S. Eaton. 

 Metaptera gracilis. Stimpson. (Agass. 

 MSS.) 



OBLONG. 



*pressus. 1 Lea. 



Sympli. compressa. Lea, in Trans. 

 Am. P. S. 



Complanaria alasmodontina. Stimp- 

 son. (Agass. MSS.) 



TJnio compressus. Con. Adams. 2 

 Linsley. Bekay. 



*decoratus. Lea. 



QUADRATE. 



*atromarginatus. Lea. Chenu. 



[ psammoicus. B' Orb. 



1 In the Proceedings of the Am. Phil. Soc, vol. ii. p. 237, I changed compressus into pressus, the former name 

 having been used by Sowerby for a fossil species. 



2 " Fresh water and land shells of Vermont." His variety plebeius does not seem to me to differ. My brother, 

 T. G. Lea, stated to me that he thought the If. pressus properly belonged to the genus Margaritana, that the charged 

 oviducts were like those of 31. complanata. In all the fifteen which he found during several years, the oviducts 

 were charged. 



