THE NAUTILUS. ' 69 



Patula alternata, Zonites arboreiis, Z. fidvus, Vallonia pulchella, 

 Succinea obliqua, S. ovalis, S. avara, Pupa armifera, P. pentodon, 

 P. corticaria, Vertigo Bollesiana, V. contracta and Carychhim exiguiim. 



Of Pupa armifera it is the first time I have found it in this 

 County. 



The above are facts, the several questions arising concerning the 

 presence of these clams here I will not answer. 



Have they worked their way from the river during compara- 

 tively recent years? or are they a sort of living connecting link 



between the lake era and the present? 



Yours very truly, 



W. S. Teator. 



THE SHELL-BEARING MOLLUSCA OF EHODE ISLAND. 



BY HORACE F. CARPENTER. 



Genus Astarte, Sowerby, 1816. 



This genus contains twenty species ; eight of these inhabit the 

 coast of Ne^v England, from Cape Cod to Greenland, and three have 

 been found south of Cape Cod, although none ot them have actually 

 been discovered in Rhode Island waters as yet. 



183. — Astarte castanea, Say. 

 •Syns. : 



Vemis castanea, Say. 



Crassina castanea, Lam. Hanley. 



Crassina sulcata, Brown. 



Venus sulcata, Mont., 3Iaton and Rackett. 



Shell thick and solid, sub-orbicular ; beaks elevated and much 

 eroded, nearly central ; lunule in front of the beaks deeply ex- 

 cavated ; surface not strongly waved as in most species of the genus, 

 but only slightly undulated, covered with a light-brown epidermis, 

 excepting on the posterior portion, where it is almost black ; hinge 

 strong ; ligament small ; valves with one stout tooth in the right 

 valve, and two in the left ; margin crenulated in adult shells. 

 Length one inch ; height one inch ; breadth Aj. 



Gould says : " The foot of the animal is of a bright Vermillion 

 color and when seen protruded, one would hardly persuade himself 

 that a red wafer was not embraced by the valves. 



