1 140 PAJ<RIvYSlA 



well out over the umbonal region ; posterior ridge not greatly 

 elevated, but usually sharply angled above, ending in a point 

 at or a little below the median line ; there is also a low, ill-de- 

 fined, radial ridge about on the middle of the disk, the base 

 of the shell being quite full where it ends ; lunule large ; an- 

 terior end rounded ; dorsal slope obliquely subtruncate ; sur- 

 face nearly smooth or with irregular, concentric sulcations; 

 epidermis ashy-green or yellowish-green with olive-green rays ; 

 pseudocardinals subcompressed, somewhat ragged ; laterals re- 

 mote, elevated ; beak cavaties moderately deep ; anterior scars 

 impressed ; posterior scars shallow ; nacre bluish-white, thicker 

 in front. 



Length 47, height 31, diam. 22 mm. 



Length 40, height 29, diam. 21 mm. 



China. 

 Unio chinensis Lea, Pr. Ac. Nat. Sci. Phila., XII, 1868, p. 



150; Jl. Ac. Nat. Sci. Phila., VI, 1868, p. 325, pi. liii, fig. 



138; Obs., XII, 1869, p. 85, pi. ijii, fig. 138. 

 Margaron (Unio) chinensis Lea, Syn., 1870, p. 30. 

 Parrcysia chinensis Simpson, Syn., 1900, p. 850. 

 Acuticosta chinensis Haas, Conch. Cab., Unio, 1912, pi. 30, 



figs. 1-3, 6-7. 



The type of this is in the collection of Yale College, accord- 

 ing to Dr. Lea, but I have before me three shells of what is 

 undoubtedly this species. They vary a little in form, coloring 

 and the degree of umbonal sculpture. One of them is not 

 very strongly sculptured on the beaks. 



\ ar. squamniosa (Heude). 



Most of the anterior part of this shell is covered with squa- 

 mose ridges. Heude merely figures the form and gives no de- 

 tails. 



China. 

 Unio sinensis var. squanimosns Heude, Conch. Fluv. Nank., 



VIII, 1883. pl- i-v"i. fig- 113- 

 Parrexsia chinensis var. sqnaniuwsus Simpson, Svn., 1900, p. 



850' 

 Acuticosta chinensis var. squamniosa Haas, Conch. Cab., Unio, 

 ■ 1912, pi. 30, fig. 5. 



