68 DESCRIPTION OP NEW 



Hab. Lake Erie— B. W. Budd, M. D. 



My cabinet and cabinet of Dr. Budd. 

 Diam. 1.1, Length 1.5, Breadth 2.1 inches. 



Shell elliptical, with a lew folds on the middle of the disk, and much inflated; substance 

 of the shell rather thick, thinner behind; beaks rather prominent; ligament short and 

 thick; epidermis yellowish-brown and much striate; cardinal teeth rather larger, double 

 in the left and disposed to be treble in the right valve; lateral teeth small, somewhat 

 bladed and curved; anterior cicatrices distinct; posterior cicatrices confluent; dorsal 

 cicatrices placed on the under side of the cardinal tooth; cavity of the shell large and 

 rounded; cavity of the beaks deep and angular; nacre white and iridescent. 



Remarks. — This is a small, undulated species, most nearly allied to U. plicatus, Lesueur. 

 A single one only is before me for examination, but Dr. Budd informs me that he re- 

 ceived about twenty specimens, all bearing the same characters. Had a single specimen 

 only been observed, I should have been disposed to consider it a stunted plicalus, with 

 more inflation than usual, and with less development of the folds. 



Unio latecostatus. PI. I. Fig. 2. 



Testa crebre plicatd, ellipticA, compressd ; valvulis crassis; naiibus prominulis; epidermide tenebroso-fusca, 

 valde striata; dentibus cardinalibus magnis; lateralibus longis subrectisque ; margaritd alba et valde 

 iridescenie. 



Shell much folded, elliptical, compressed; valves thick; beaks slightly prominent; epidermis dark-brown, much 

 striated; cardinal teeth large; lateral teeth long and nearly straight; nacre white and very iridescent. 



Hab. Tuscaloosa, Alabama. B. W. Budd, M. D. 



My cabinet and cabinet of Dr. Budd. 

 Diam. 1.3, Length 2.5, Breadth 3.5 inches. 



Shell very much folded over the whole disk, with thick ribs, visible on the inside, remark- 

 ably oval, much compressed; substance of the shell thick before, thinner behind; beaks 

 scarcely prominent; ligament long and rather thick; epidermis very dark-brown, nearly 

 black and much striate; cardinal teeth very large and thick, double in the left and single 

 in the right valve; lateral teeth long, rather thin, and nearly straight; anterior cicatrices 

 distinct; posterior cicatrices confluent; dorsal cicatrices placed on the under side of the 

 cardinal tooth; cavity of the shell very shallow; cavity of the beaks shallow and some- 

 what angular; nacre white, tinged with purple on the posterior margin, and very 

 iridescent. 



Remarks. — But two specimens of this species were received by Dr. Budd, and my 

 cabinet is indebted to him for one of them. The large, regular, and thick fold, and 

 regular oval margin distinguish this shell from the proximate species. It is perhaps most 

 closely allied to U. undulahis, Barnes, but may be distinguished at once by its oval form, 

 and the number and regularity of its folds or ribs, which are remarkably parallel. The 

 posterior portion of the valves being rather thin, causes the thick ribs to be impressed 

 on the inside, which has a very unusual and brilliant, iridescence, tinged with purple in 

 the nacre. The cardinal teeth are very large in proportion to the lateral teeth. 



