378 NEW EXOTIC UNIONIDiE. 



mis shining, black, striate and without rays; cardinal teeth rather small, com- 

 pressed, oblique, suberect and crenulate ; lateral very long, crenulate and straight ; 

 nacre white and iridescent. 



Hob. — Uruguay River, South America, Prof. J. Wyman. 



My cabinet. 

 Diam. -7, Length 1-1, Breadth 2 inches. 



Shell smooth, oblong, somewhat inflated, flattened at the side, very inequilateral, 

 biangular behind, rounded before ; substance of the shell somewhat thick, thicker 

 before; beaks somewhat prominent and flattened, with diverging undulations at 

 the tips ; ligament rather long, thin and light-brown ; umbonial slope somewhat 

 raised and obtusely angular; posterior slope long elliptical, somewhat wrinkled, 

 with a moderate carina ; cardinal teeth rather small, compressed, oblique, suberect, 

 crenulate and double in both valves ; lateral teeth very long, crenulate and straight ; 

 anterior cicatrices rather small, well impressed, confluent with the lower, but distinct 

 from the upper ; posterior cicatrices rather large, confluent and slightly impressed ; 

 dorsal cicatrices placed nearly in the centre of the cavity of the beaks ; cavity of 

 the shell rather £deep and wide ; cavity of the beaks very shallow and rounded ; 

 nacre white and iridescent. 



Remarks. — A single specimen only was received of Prof. Wyman, and this not 

 very perfect. The beaks are very much eroded, but yet are perfect enough to show 

 some of the undulations which still remain in the nacre, while the epidermis is 

 removed. While it reminds one of a half-grown parallelopipedon (nobis), it is by 

 no means so wide. In outline it really is closer to Mississippiensis, Con., but it 

 differs in color entirely, that shell being beautifully rayed, while this apparently has 

 no rays whatever. It is also higher in the umbonial slope, and the cardinal teeth 

 are smaller and more compressed. 



Unio funebralis. PI. 41, fig. 286. 



Testa lasvi, subrotunda, compressissiina, inaequilatcrali, autice ct postice rotundata ; valvulis erassis, 

 antice crassioribus ; natibus proinimilis, compressis ; cpidermide nigricante, striata, ad apices mi- 

 cante, cradiata; dentibus cardinalibus parviusculis, subcornpressis, tripartitis ; lateralibus sublongis 

 valde curvisque ; margarita vel alba, vel salmonis colore tincta. 



Shell smooth, subrotund, very much compressed; inequilateral, rounded before 

 and behind ; valves thick, thicker before ; beaks somewhat prominent, compressed ; 

 epidermis blackish, striate, shining at the beaks, eradiate ; cardinal teeth rather 

 small, rather compressed, tripartite ; lateral teeth rather long and very much 

 curved, nacre white or salmon color. 



Rab: — Uruguay River, South America, Prof J. Wyman. 



My cabinet. 



