CUMINGIA. 79 



of M. soUdissima and M. ovalis arc much less triangular, and of 

 a Tcrj different aspect. It has more the proportions of M. solida 

 of Em'ope. 



Ocntis CUMINGIA, Broderip and Sowerby. 1833. 



Shell ovate, inequipartite, eqnivalve ; a shallow, spoon-shaped 

 cardinal tooth, and a single small tooth hj its side in each valve, 

 and a strong lateral tooth on both sides in one valve only ; pallial 

 impression with a large sinns. 



Cumingia tellinoides. 



Fig. 36. 



Shell ovate-triangular, thin, white, nearly equipartite, pointed and warped 

 behind ; surfoce with sharp, elevated lines of growth. 



Mactra tellinoides, Conrad, Journ. Ac. Nat. Sc. vi. 258, pi. 9, figs. 2, .3 ; Amor. Mar. 



Conch. 60, pi. 14, tig. 2. — Russell, Essex Journ. Nat. Hist. i. 53. — De Kay, Nat. 



Hist. New York, 233. 

 Cumingia tellinoides, Conrad, Journ. Ac. Nat. Sc. vii. 234. — Gould, Inv. 1st etl., fig. 



36. — Stimpson, Shells of New England, 20. 



Shell elongated, triangular-ovate, thin, fragile, bluish-white; 

 nearly equipartite, anteriorly broad, tumid, and regularly rounded ; 

 posteriorly compressed, warped, ending in a rounded point, the 

 margin declining more rapidly than in front ; beaks 

 raised, not inclining to either end. Stages of growth ^'s- 390. 

 marked by sharp, raised ridges, which are crossed by 

 microscopic, radiating lines ; in front of the beaks is a 

 small, well-defined areola. Within, glossy-white; pit c. leiunoides. 

 for the cartilage shallow, directed slightly backwards ; 

 in front of it, in each valve, is a linear tooth forming part of its 

 wall, and at its side a fossa for receiving the corresponding tooth ; 

 lateral teeth distinct in the right valve, but wanting in the left, 

 the anterior one longest. Muscular impressions faint, pallial im- 

 pression far within the shell, Tvith a broad, deep indentation oppo- 

 site the base. Length, three fifths of an inch ; height, nine twen- 

 tieths of an inch ; width, one fifth of an inch. 



Found alumdantly in the region of New Bedford, Martha's Vine- 

 yard, and probably may be found everywhere south of Ca})e Cod. 



Its warped, slightly folded end gives it the aspect of a Tellina. 

 Its shape and surface are similar to those of Corhida contracta of 



