COMPLETE GRAU : PECTINIDAE OF THE EASTERN PACIFIC 73 



ornamented by riblets of equal prominence to those forming the fasci- 

 culi ; anterior ear with about seven equal, prominently imbricated radials ; 

 posterior ear short and with radial and imbricating sculpture; byssal 

 notch quite prominent. Left valve similar to right, but with the fasciculi 

 corresponding to the interspaces of the right valve, and consequently 

 much narrower than the fasciculi of that valve. Color, white to very 

 light pink. 



Alt. 45 mm.; long. 40 mm.; hinge line 19 mm.; diameter 14 mm. 



Remarks: The descriptions of Pecten hastatus albidus and P. 

 (Chlamys) erythrocomatus are so similar that it would be impossible to 

 definitely refer a specimen to either by relying on them. At the author's 

 request Dr. Harald A. Rehder examined the holotypes of both and con- 

 cluded "... I would be inclined to unite them." 



Chlamys islandka albida is quite variable in form and sculpture. 

 The disk may be longer than high or nearly circular, either flatly convex 

 or rather deeply so ; the ribs vary in number and may be well or poorly 

 defined; the number of ribs varies; the imbricating sculpture varies in 

 profusion and prominence. 



The broad, low ribs and smaller auricles (particularly the posterior), 

 are the chief differences between this subspecies and the typical. From 

 C. islandica behringiana it differs in rib-structure and sculpture. 



Geographical range: Bering Sea through the Aleutian Islands, Ok- 

 hotsk Sea and Kurile Islands to Japan; Pacific coast of Japan as far 

 south as 45° N, Japan Sea as far south as 48° N. 



Geochronological range: Known only from the Recent. 



Bathymetric range: 50 to 100 fathoms, possibly deeper. 



Ecological data : None available. 



Chlamys islandica behringiana (Middendorff) 1849 



Plate 23, fig. 2 



Pecten Islandiciis, van Behringiana Middendorff, 1849, p. 528, pi. 13, 

 figs. 1-3. ". . . im Behrings-Eismeere . , ." 



P. Hindsii var. strategus Dall, 1898, 704. [Nomen nudum; no "indica- 

 tion, definition or description."] 



Pecten hericeus var. strategus Dall, 1898, p. 709. "Pleistocene of Alaska 

 and recent at Unalashka." 



Pecten (Chlamys) hericeus var. strategus Dall. Arnold, 1903, p. 110, 

 pi. 11, fig. 5. Living: Unalaska. Pleistocene: Alaska; San Pedro. 



Pecten (Chlamys) hastatus Sowerby var. strategus Dall. Arnold, 1906, 

 p. 113, pi. 44, figs. 2, 2a, 3, 4. Living: Unalaska. Pleistocene: 



