CHIEFLY OF THE UNITED STATES. 325 



impressed; dorsal cicatrices indistinct; cavity of the sliell shallow and wide; 

 cavity of the beaks very shallow ; nacre pale green and not iridescent. 



Remarks . — Two odd valves — a right and left — were sent to me by the Smithsonian 

 Institution. The larger and more perfect one is figured, but that is not perfect on 

 the dorsal margin, while the epidermis is nearly perfect. Both the specimens have 

 the epidermis covered with the wrinkled festoon-like character. In outline it is near 

 to Schroeteriana (nobis), but it is of a more perfect ellipse and is a thicker shell. Like 

 crispata, Lam., it is covered with wrinkles, but it is more likely to be confounded 

 with tenehricosa (nobis) from the dark color of the nacre and thickness of the shell. 

 It may, however, be easily distinguished by its being elliptical, while the other is 

 oblong, having a higher elevation of the posterior slope. 



Unio Chinensis. pi. 53, fig. 138. 



Testa nodulosa, subelliptica, inflata, fere sequilaterali, postice obtuse angulata, antice rotunJata ; 

 valvulis crassiusculis, antice crassioribus ; natlbus subpromineotibus, ad apices corrugatis ; 

 epidermide virido-lutea, radiis viridis undique indutis ; dentibus cardinalibus erectis, compressis, 

 striatis, crenulatis et in utroque valvule subduplicibus; lateralibus sublongis subrectisque ; 

 margarita argentea et valde iridescente. 



Shell nodulous, subelliptical, inflated, nearly equilateral, obtusely angular behind, 

 rounded before ; valves somewhat thick, thicker before ; beaks somewhat prominent, 

 corrugate at the tips ; epidermis greenish-yellow, covered all over with green rays ; 

 cardinal teeth erect, compressed, striate, crenulate, and in both valves subduplicate ; 

 lateral teeth rather long and nearly straight ; nacre silver-white and very iridescent, 

 Proc. Acad. Nat. Sci. 1868, p. 150. 



Hah. — Hong Kong, China. 



Cabinet of Yale College, New Haven, Conn. 

 Diam. -9, Length I'l, Breadth 1-7 inch. 



Shell nodulous, subelliptical, inflated, nearly equilateral, obtusely angular behind, 

 rounded before ; substance of the shell somewhat thick, thicker before ; beaks 

 somewhat prominent, corrugate at the tips; ligament very short and narrow; 

 epidermis greenish-yellow, covered all over with beautiful green rays, with very 

 distant lines of growth; umbonial slope raised and sharply angular; posterior slope 

 flattened, cordate, with two lines from beaks to posterior margin on each valve ; car- 

 dinal teeth erect, compressed, striate, crenulate, disposed to be double in both valves ; 

 lateral teeth rather long and nearly straight; anterior cicatrices distinct and well 

 impressed; posterior cicatrices confluent and slightly impressed; dorsal cicatrices 

 set deeply within the cavity of the beaks ; cavity of the shell deep ; cavity of the 

 beaks deep and angular; nacre silver-white and very iridescent. 



