COMPLETE GRAU : PECTINIDAE OF THE EASTERN PACIFIC 71 



Pecten (Pecten) islandicus Miiller. Grant & Gale, 1931, p. 161, pi. 11, 



figs, la, lb. "Pliocene: Raised beaches at Nome, Alaska (Dall) ; 



uppermost Pliocene of Ventura County, California (Waterfall). 



Pleistocene: "Pliocene" of Deadman Island, San Pedro (Arnold) ; 



. . . Clyde beds of England (Wood) [1850, p. 40, pi. 5, fig. 1]." 



Living: Dall records cited; also "Scandinavia and North Scotland 



(Wood)." 

 Pecten (Chlamys) islandicus Miiller. Proc. Conch. Club So. Calif., 



1944, no. 35, p. 8. ". . . not of the Pacific coast fauna . . . never 



. . . south of the Bering Sea." 

 Holotype: Lost. 



Type locality: Iceland. 

 Original description: Testa orbicular! aurita, circulis purpureis, 

 radiis 100. 



Additional description : Shell rather large, adult specimens averaging 

 80 mm in height and often reaching 100 or more; usually slightly higher 

 than long. Convexity moderate and variable, with valves nearly equal. 

 Hinge margin about half as long as disk. Both valves often having low 

 radial folds of varying width. Number of ribs variable, usually from 

 60 to 100; ribs low, narrow, and of equal width or irregularly varying, 

 with both bifurcation and intercalation usually present. Sculpture quite 

 variable; whole surface of disk finely imbricated, or ribs imbricated and 

 interspaces minutely reticulated. Anterior auricle of right valve well 

 produced and imbricated, having 4 to 6 major riblets and varying num- 

 ber of smaller ones; byssal notch moderately pronounced and ctenolium 

 having 4 to 6 teeth; posterior auricle much smaller, imbricated, with 

 varying number of fine riblets and usually having vertical ridges of 

 growth. Anterior auricle of left valve having moderate byssal sinus, 

 imbricated, and with varying number of riblets; posterior auricle cor- 

 responding to that of right valve. Color range: brown-red, red, pink, 

 red-orange, orange-yellow, yellow and white, often with concentric 

 bands of lighter and darker shades. 



Remarks: Although extra-limital, this species is included in the 

 present paper because of the frequent references to it in literature on 

 the eastern Pacific fauna south of the Bering Sea. Records from south- 

 ern Alaska, British Columbia and Puget Sound were the result of mis- 

 identifications. Chlamys islandica varies considerably in number of ribs 

 and in sculpture, but is quite distinct, and easily separable from its sub- 

 species albida (Dall) and behringiana (Middendorff). 



