ANATINA. 67 



Shell small, broadly rounded-ovate, fragile and thin, white and 

 pearly ; the right valve most convex ; inequijiartite, the posterior 

 or shorter side narrowed, and at the tip cli})pcd, and moderately 

 gaping; margin, from the beak backward, a 

 straight line ; the rest of the outline regularly ^'=- ^'^^■ 



curved with a slight inflection of the posteal 

 ventral margin ; beaks placed about one third 

 of the length of the shell from the posterior 

 extremity, moderately prominent, inclining 

 forwards, and cleft across the middle ; from 

 the beaks to the lower posterior angle runs A.papyracea. 



an elevated, angular ridge; surface finely 



marked by the lines of growth, with vestiges of a yellowish white 

 epidermis ; interior pearly ; tooth long and narrow, slightly con- 

 cave, directed obliquely across the shell, supported beneath by a 

 short, sharp, elevated rib ; muscular and pallial impressions very 

 superficial. Ossiculum somewhat like two crescents joined at the 

 extremities, fitting in front of the teeth. Length, thirteen twen- 

 tieths of an inch ; height, one half of an inch ; breadth, one fourth 

 of an inch. A fine specimen taken at Anticosti Island l)y Dr. 

 Packard was three times as large. 



Found in the stomachs of fishes caught off Nahant ; and taken 

 by dredging in Newport Harbor by Colonel Totten. In three fath- 

 oms, fine sand, east of Deer Island, and in four fathoms, soft mud, 

 off the Navy Yard ; from Cape Ann, southward (^Sti/npson^ ; East- 

 port (^Cooper} ; Sable Island QWilUs^ ; Anticosti Island (^Packard). 

 The animal has the foot long, cylindrical, opaque white, and 

 wrinkled across. 



This is undoubtedly the shell described at length by Colonel 

 Totten, and for Avhich he proposes the specific name frag-ilis, pro- 

 vided it Ije not the A. papyratia of Say. Mr. Say's dimensions 

 differ a little in their proportions from the New England shell ; 

 but our shells have sufficient latitude of dimensions to render this 

 variation of little importance. 



The only shell we have that resembles it is the Macoma fusca ; 

 but that shell has less thickness, is equilateral, and rounded through- 

 out, besides the great difference of the hinge. It is also very like 

 TJiracia m//opsis, but is well marked by its spoon-like cartilage 

 pits and acute supporting rib. 



