TAUREYSTA II41 



Var. Icpvis (tleiide). 



Shell large, nearly or (juite destitute of sculpture, with broad, 

 dark rays. 



China. 

 Unio sinensis var. Iccvis Hijude, Conch. Fluv. Nank., VIII, 



1883, pi. i,ix, fig-. 116. 

 Parreysia chinensis var. Icrzns Simpson, Syn., 1900, p. 850. 

 Acuticosta chinensis var. hcvis Haas, Conch. Cab., Unio, 19 12,. 



pi. 30, fig. 4. 



Parreysia retiaria (Heude). 



vShell rather small, inflated, solid, somewhat inequilateral ; 

 beaks full and high, turned forward ; anterior end rounded ; 

 base line nearly straight ; outline of dorsal slope obliquely 

 rounded ; posterior ridge full, narrowly rounded, ending in a 

 feeble biangulation almost at the base of the shell ; in front 

 of the posterior ridge there is a wide, radial, somewhat de- 

 pressed space ; epidermis fuscous horn-color, slightly rayed ; 

 pseudocardinals solid, split up ; nacre amethyst-rose. 



Length 22, height 15, diam. 10 mm. 



Streams of Ning-kouo fou and of Tche-tcheou fou, China. 

 Unio retiarius Heude, Conch. Fluv. Nank., \"ni, 1883, p. 



LVii, fig. 107. 

 Parreysia retiaria Simpson, Syn., 1900, p. 850. 

 Acuticosta retiaria Haas, Conch. Cab., Unio, pi. 30, fig. 12. 



A fine, small species, which probably is related to P. chin- 

 ensis. Its most conspicuous character is the wide, radial, de- 

 pressed area in front of the posterior ridge. 



SPECIES INCERT.^ SEDIS 

 Parreyssia alluaudi Dautzenberg. 



"Shell very thin, shining, elongate-oval, rounded in front, 

 truncate and rostrate behind. Ventral margin convex and pro- 

 jecting in the middle. Beaks inflated, quite prominent. Sur- 

 face .sculptured in the umbonal region with oblique, zigzag 

 folds, which extend more or less over the whole of the disk. 



