U X I o , 



O.J 



WIDE. 



Novas Hollandice. Gray. Ilan. 



*cylindricus. Say. Sh. & Eat. Ilild. 

 Han. Swain. Chenu. 

 Unio naviformis. Lam. Blain. 



Yalen. Desk. 1 

 My a cylindrica. Eat. 



r TRIANGULAR. 



%pinosus. Lea. Chenu. Han. 

 Canthyria spinosa. Swain. 



*collinus. Con. 



QUADRATE. 



*Wymanii. 2 Lea. 

 Aveia. Ben. 



TRIANGULAR. 



*Kraussii. 3 Lea. 



Castalia sulcata. Krauss. 



*rubidus. Lea. 



*negatus. Lea. 



*Averyi. Lea. 



*encarpus. Lea. 



*Gabbianus. Lea. 



*Granaclensis. Lea. 



*Estabrookianus. Lea. 

 Unio striatissimus. Anth. 



V. 



H 



TRIANGULAR. 



*Nicaraguensis. 4 Lea. 

 *planior. Lea. 

 *rugososulcatus. Lea. 

 *Meredithii. Lea. 



OVAL. 



*stramineus. Con. Han. 

 *Gerbardtii. Lea. 

 *aratus. Lea. 

 *Dysonii. Lea. 

 *CaldweIlii. Lea. 

 *tripartitus. Lea. 

 *Rowellii. Lea. 

 melleus. Lea. 

 *Paramattensis. Lea. 

 *effulgens. Lea. 

 *vittatus. Lea. 

 *Syriacus. Lea. 



OBLONG. 



*Scamnatus. 5 More. 



Unto Grundlachi. Dunk. 



1 Deshayes, in Enoly. Meth. Vers., torn. ii. p. 580, No. 5. 



2 Von Martens considers Wymanii to be a synonym to delodontus, Lam.; but, on a re-examination of 

 the specimens, I am surprised at his conclusion. 



3 Dr. Dunker, at Cassel, gave me a shell under the name of Castalia sulcata Krauss, from Surinam. 

 But it is not a Prisodon (Castalia); for, although it has the outline and general appearance, the teeth are 

 not striate, but granulate. It therefore belongs to the triangular Uniones, and the name of Unio sulcata 

 being preoccupied it must be changed, which I do to that of the able discoverer, Prof. Krauss— Unio 

 Kraussii. This species has remarkable transverse furrows like some of the species of Cyrena. 



* Lake Nicaragua, C. A. 



5 This very distinct and interesting species is from Cacajagicara River and Taco-taco River, Cuba. 

 It is covered with transverse furrows. 



