800 PROCEEDINGS OF THE NATIONAL MUSEUM. voL.xxii. 



knobs ; surface strongly pustulous ; beaks rather well forward, sculpture 

 not seen; epidermis concentrically wrinkled, black and rough; pseudo- 

 cardinals strong, somewhat radial, rough, striate; laterals more or less 

 vertically striate, secondary lateral in right valve well developed ; beak 

 cavities very deep, compressed; posterior calluses faint. 

 Animal unknown. 



tQUADRULA ROCHECHOUARTI Heude. 



'Unio rocheckoum-ti Heude, Concli. Fluv. Nank., I, 1875, pi. v, fig. 13; "Jahrb. 

 Deutsch. Mai. Ges., VIII, 1881, p. 122.— ■ PiETEL, Conch. Sam., Ill, 1890, 

 p. 165. 



China. 



(Group of Quadrula triclava.) 



Shell solid, elongate triangular, obtusely pointed at the posterior 

 base, with a decided posterior ridge, along which runs a row of pon- 

 derous knobs; beaks high and far forward; surface strongly nodulous; 

 posterior slope slightly corrugated ; epidermis dark chestnut ; pseudo- 

 cardinals heavy, subradial, radially striate; laterals vertically striate, 

 secondary lateral of right valve well developed; cavity of the beaks 

 enormously deep and compressed; a granular callus behind the late- 

 rals; nacre silvery, radially granularly striate outside the pallial line. 



tQUADRULA TRICLAVA Heude. 



^ Unto triclavus Heude, Conch. Fluv. Nank., II, 1877, pi. x, figs. 21, 21a. — *P/ETEL, 

 Couch. Sam., Ill, 1890, p. 170. 



China. 



(G-roup of Quadrula bazini.) 



Shell elongate-trigonal, with a fairly well developed posterior ridge, 

 pointed behind; beaks not high, almost at extreme front of the shell; 

 surface more or less covered with knobs and tubercles, which show a 

 tendency to an arrangement in curved lines; epidermis chestnut to 

 blackish; hinge strong; pseudo-cardinals radial, radiately striate; lat- 

 erals granular, showing traces of vertical striation; beak cavities very 

 deep, compressed; nacre silvery. 



Animal unknown. 



tQUADRULA BAZINI Heude. 



* Unio bazini Heude, Conch. Fluv. Nank., II, 1877, pi. ix, fig. 20. — *P*:tel, Conch. 

 Sam., Ill, 1890, p. 145. 



China. 



(Group of Quadrula leai.) 



Shell obovate, obtusely pointed behind; posterior ridge low; whole 

 surface generally tuberculate or knobbed, with strong, radial, curved 



