152 INVERTEBRATA OF MASSACHUSETTS. 



the area on the anterior valve is shaped Hke the valve. The re- 

 maining portion of the valves is smooth, with three radiating lines 

 passing from the beaks to the middle of each base, enclosing two 

 rounded, threadlike ribs. It is also covered with a thin mem- 

 brane, coated with a dirty, scurfy epidermis which is easily 

 rubbed off. Margin broad and thick, resembling macerated calf- 

 skin, coated like the rest of the surface, and having two ranges 

 of small tufts of yellowish hair, two on each of the intermediate, 

 and six or eight around the terminal valves. Length | inch, 

 breadth j% inch. 



Found in the stomachs of fishes taken in Massachusetts Bay. 



This is a very curious shell, and, with three or four other described 

 species, might constitute a sub-genus. It is so rough and unseemly 

 that it is very likely to be rejected as some decayed specimen ; or the 

 discoverer would begin to clear off, as some extraneous substance, 

 the coating which belongs to it, and gives it a charactei*. 



The shape of the valves, the sculptured areas, and the emarginate 

 anterior valve, will not allow it to be confounded with any other spe- 

 cies. Could it be presumed that so remarkable characters as the cen- 

 tral areas and the anterior valve were overlooked, we might suppose 

 this to be the C. vestitus, Brod. and Sowerby (Zool. Journ., iii. 368.) 

 The areas, however, are easily defaced, and might not have attracted 

 notice in their specimens. In other respects their description would 

 apply well to our shell. The figure recently given of it, in the Ap- 

 pendix to Beechey's Voyage, represents a shell proportionally much 

 narrower than ours. 



Genus PATELLA. Lin. 



»S7tc// low-conical, apex nearly central and inclining a little for- 

 ivards ; aperture ohlong-oval^ cavity hasin-shaped. 



Pate'lla ca'ndida. 



Shdl small, white, with numerous diverging ribs, checked by 

 revolving lines, apex central. 



State Coll., No. 124. Soc. Cab., No. 2381. 



Talella Ciindida, Couthouv ; Host. Journ. JVat. Hist., ii. ii(j, pi. 3. f. 17. 



