M A E G A E I T A ?f A . 



67 



lY. SUBGENUS MARGARITAXA/ 







^ 





•^ 





< 





H 









M 





<! 





Ct 





« 





<3 

















W \ 





H 





O 





a 



^ 















Ph 









r^ 













^ 





O 





^ 



L 



TRIANGULAR. 



*complanata. Bar. Lea. 



Alas, complanata. Bar. Hild. Sow. 

 Symph. complanata. Lea. Sh. & Eat. 

 Unio complanata. Desh. Han. 

 My a complanata. Eat. 



QUADRATE. 



*confragosa. Say. Lea. 

 Alas, confragosa. Say. 

 Unio confragosa. Desh. Han. 



TRIANGULAR. 



*arcula. Lea. 



Alasmodonta arcula. Chenu. Han. 



OBLONG. 



*inarginata. Say. Lea. 



Alas, marginata? Say. Bar. Gould. 



Migh. Lins. Dekay. Stimp. 

 Alas, truncata? Say. 

 Unio cariosa. (Var. 2.) Lam. 

 Unio varicosa. Lam. 

 Unio caleeolus. Say, not of Lea. 



OBLONG. 



Uiio marginatus. Heeve. Han. 

 Mya regulosa. Wood. Han. 

 Mya rugosa. Eat. 

 Alas, corrugata. Dekay. 

 Vignouana. Bern. 



*rugosa.* Lea. Kirtl. 



Alas, rugosa. Bar. Sh. & Eat. Hild. 



Adams. Dekay. 

 Alas, ahducta. Say. 

 Coinplanaria rugosa. Siuains. Stimp- 



son. (Agass. MSS.) 

 Unio rugosus. Gheiiu. Han. 



t f OBLONG. 



S I *Gesnerii. Lea. 



( TRIANGULAR. 



*deltoidea. Lea. 



Alasmodonta deltoidea. Chenu. Han. 



*niinor. Lea. 



Alasmodonta rninor.' Chenu. 



^ The genus Mo-rgaritana was proposed by Scliiimacher, in his Essai d'un Nowveau Systeme des 

 Habitations des Vers Testaces, published in 181T, for the Mya margaritifera, Lin. (Unio elongata, Lam. 

 and Alasmodonta arcuata.. Bar.). Mr. Say, in 1818, propiosed to establish this same division under the 

 generic name of Alasviodonta. The Danish zoologist, having priority of date, must have his name pre- 

 ferred. Mr. Gray, in his Genera., adopts Margaritana, but he cites Bapliia, Gevers, in 1787. H. and A. 

 Adams, in Genera of Rec. 3IoL, give Baphia preference, and cite Meuchen, in Museum Geversianum, 

 1787, as having i^riority, which I think is correct; and they make the following subgenera — Alasmodonta, 

 Say, Gomplanaria, Swain., Galceola, Swain. 



' This sj)ecies has a very wide geographical distribution. In the St. Lawrence and in the Northern 

 States, it is of ordinary size as it is in the Middle States ; but in Ohio it is found large and thick, and 

 very perfectly developed. In South Carolina, Georgia, and Tennessee, it is smaller ; and in Kansas, in 

 Verdigris River, it is very much like those in Pennsylvania. 



^ Several specimens of fine marginata have been sent to me from the west, marked Alas, truncata, 

 Saj', being one of his unpublished names, but specimens given by him to various conchologists under 

 that name. I have never considered it distinct from the marginata of the eastern rivers, although it is 

 generally larger and of finer color in the exterior. 



* I found the oviducts of M. rugosa fullj^ charged on the 20tli May. 



