AND OTHER FAMILIES. 97 



Remarks. — This species has, perhaps, most resemblance in its exte- 

 rior to the marginalis (Lamarck), which comes from the great rivers 

 of India. In the interior, however, it differs much. Our shell is of a 

 very dark salmon colour. It is also a thicker shell, and the teeth are 

 much thicker. In the colour of the epidermis it somewhat resembles 

 the lanceolatus (nobis). 



Unio modioliformis. Plate XIII. fis:. 40 



»• 



Testa ovatd, traiisversd, inseqitllaleraU, injlatd, antice angustd, postice lata ; 

 valvulis tenuissimis ; natibus minutis et fere terminalibus ; dentibus cardinalibus 

 parvis, compressls, laieralibus hngis ciirvisque; margaritd siibpurpured, valde 

 iridescenti. 



Shell ovate, transverse, very inequilateral, inflated, narrow before and broad behind ; 

 valves very thin ; beaks small, nearly terminal ; cardinal teeth small, compressed ; 

 lateral teeth long and curved ; nacre slightly purple, very iridescent. 



Hab. Santee Canal, South Carolina. Professor Ravenel. 



My Cabinet. 



Cabinet of Professor Ravenel. 



Cabinet of P. H. Nicklin. 



Diam. 1-1, Length 1-5, Breadth 2-7 inches. 



Shell reversely ovate, transverse, very inequilateral, inflated, narrow 

 before and broad behind, emarginate at basal margin ; substance of the 

 shell very thin, diaphanous ; beaks small, nearly terminal, slightly un- 

 dulated; ligament rather long and thin; epidermis brown, shining; rays 

 indistinct; cardinal teeth small, compressed, disposed to be double in 

 the left and single in the right valve ; lateral teeth long, curved and ele- 

 vated in their direction ; anterior cicatrices distinct ; posterior cicatrices 

 confluent; dorsal cicatrices small, situated in the cavity of the beaks; 

 cavity of the shell deep ; cavity of the beaks shallow ; nacre slightly 

 purple, very iridescent. 



Remarks. — The spreading out of the posterior portion of the shell, 

 and the narrowness of the anterior portion, is very striking in this spe- 



YOL. V. Z 



