12 AMERICAN JOURNAL 



DESCRIPTION OF A NEW SPECIES OP RISSOA. 



BY GEORGE W. TRYON, JR. 



Eissoa exilis, Tryon. — t. 2, f. 18. 



Description. — Shell subulate, light brown, consisting of six 

 convex volutions, with well-marked suture; aperture oval, 

 proportionally very small ; surface covered with slight re- 

 volving striae ? 



Dimensions. — Length "135 inch, diameter *07 inch ; length 

 of aperture '04 inch, breadth *03 inch. 



Habitat. — San Diego, Cal., on salt water grass, (Dr. J. G. 

 Cooper.) 



My Cabinet. 



Observations. — I find only a single specimen of this very 

 distinct Rissoid among a lot of R. Coojierii, nob. There ap- 

 pear to be traces of revolving striae on this specimen, which 

 is, unfortunately, not in good condition, being a dead shell. 



