PECTEN, 199 



disposed, radiating ridges, bearing a multitude of erect, vaulted 

 scales ; their ridges are grouped so as to form a number of unequal 

 ribs, wliicli are better defined on the interior of the shell. Ears un- 

 equal ; posterior one shorter, and its angle slightly obtuse, alike in 

 both valves, and covered with scaly, radiating ridges ; the anterior 

 ear of the right valve is more deeply notched than that of the left, 

 and has five radiating ribs, occupying about two thirds of its sur- 

 face. Valves closed except at the notch ; color passing from light 

 orange to dark reddish-brown ; the upper valves usually zoned, or 

 blotched, with deeper colors, and the lower valve much the lightest. 

 The margin jagged by the elevated lines, all but the notch of the 

 right valve, which is plain, excepting that there are five or six 

 minute teeth in the angle. Interior white and glossy, the left valve 

 usually having a large roseate spot near the beaks. Length, three 

 inches ; height, three and one half inches ; breadth, one inch. 



Occasionally found, of a small size, in the stomachs of fishes. Its 

 proper residence, however, seems to be the Newfoundland Banks, 

 where it is a favorite food of fishes. Eastport ( Cooper^ ; Halifax 

 ( Willis^ ; W. C. of Greenland {Hayes} ; Cape Hope, James's Bay, 

 lat. 52^ 10', fossil {Drexler} ; Eastport to Connecticut {Stimpson}. 



In a young state the vaulted scales do not appear ; but the inter- 

 stices between the ribs are filled with a beautiful lozenge-shaped or 

 tile- work sculpture, which may usually be seen near the beaks in 

 adult specimens. The colorhig varies greatly, and has given rise to 

 two or three synonymes. 



Pecten irradians. 



Fig. 88. 



Shell orbicular, ears sub-equal, valves convex, nearly closed, with about twenty 

 rounded ribs. 



Pecten irradians, Lam. An. sans Vert. 2d ed. vii. 143. — Stimpson, Shells of New Eng- 

 land, 8. 



Pecten concentricus, Say, Journ. Acad. Nat. Sc. ii. 2.59 (1822). — Conrad, Amer. Mar. 

 Conch, pi. 1, fig. 2. — De Kay, N. Y. Moll. 172, pi. 9, fig. 205. —Gould, Invert. 

 1st cd. 134, fig. 88. 



Shell nearly round, rather strong ; valves convex, the lower very 

 little less so than the upper one, with about twenty elevated, rounded 

 .ribs, the depressed spaces being similarly rounded, and about equal 

 to the ribs in width ; loosely wrinkled concentrically by fine lines 

 of growth. Usual color a dusky or blackish horn color, with alter- 

 nately darker and lighter zones. Ears two thirds of the length of the 



