B Y S S A X O D O X T A . 



87 



X. SUBGENUS BYSSAXODOXTA. 1 



QUADRATE. 



Paranensis. D'Orl. Chenu. 



1 This is a remarkable fresh water bivalve discovered by M. D'Orbigny, remaining always attached 

 by a byssus. See Voy. dans I'Amer. Mr rid. 



