302 AMERICAN JOURNAL 



DESCRIPTION OF A NEW SPECIES OF SEPTIFER. 



BY GEORGE W. TRYON, JR. 



Septifer Trautwineaxa, Tryon. — t. 20, fig. 8. 



Description. — Shell mytiliform, obtusely angulate medially, 

 and with a carina extending from the beak to the centre of 

 the posterior basal margin ; lines of groAvth irregular, rugose ; 

 epidermis dark brown. Septum deeply sunken, with a longi- 

 tudinal lamina under its posterior side. On the anterior mar- 

 gin, near the beaks, one valve is produced into a tooth, which 

 clasps into a sinuosity in the other. 



Dimensions. — Length 37, breadth 16, height 18 mill. 



Hahitat. — River San Juan, New Granada. 



Cabinet of Isaac Lea, LL.D. 



This large species was obtained by Mr. Trautwine in the 

 River San Juan, a small stream, emptying into the Pacific in 

 latitude 4°. Mr. Lea kindly communicated it to me for de- 

 scription. 



