THE FAMILY NAIADES. 



i3 



SUBGENUS MARGARITANA.* 



TRIANGULAR. 



complanata. Lea. 



Alas, complanata. ^ar. i^eYfl?. 

 Symp. complanata. Lea, Trans. Am. 

 P. S. 



QUADRATE. 



confragosa. Lea. 



Alas, confragosa. Say. 



TRIANGULAR. 



arcula. Zea. 



OBLONG. 



marginata. Lea. 



Alas, marginata. ^«y. Bar. 



* The genus Margantaiia was proposed by Schumacher m his " Essai 

 d'un Nouveau Systeme des Habitations des Vers Testac^s" pubHshed in 

 1817, for the Mija margaritifera, Lin. {Uiiio elongata, Lam. and Alasmo- 

 donta arcuata, Bar.) Mr. Say in 1818 proposed to estabUsh this same divi- 

 sion under the generic name of Alasmodonta. The Danish zoologist having 

 priority of date must have his name preferred. 



