COMPLETE GRAU : PECTINIDAE OF THE EASTERN PACIFIC 75 



ridges ; byssal notch prominent ; posterior ear nearly obsolete, sculptured 

 similarly to right [anterior]. Left valve resembling the right except that 

 the ribs are narrow^er, more convex, and with the intercalary riblets 

 usually more imbricated ; interspaces broader than in right valve ; an- 

 terior ear with about 8 imbricated ridges. Color of recent specimens 

 bright scarlet. Alt. 35 mm.; long. 34 mm.; hinge line 17 mm., dia- 

 meter 16 mm.; umbonal angle 83 mm. [83°]. This variety is easily dis- 

 tinguished by its few broad ribs, which increase in number very rapidly 

 both by division and intercalation after reaching an altitude of about 20 

 millimeters. Arnold, 1906, describing P^c/^ra (Chlamys) hastatus Sower- 

 by var. strategus Dall. 



Remarks: The Bering Sea, for which Middendorff named this sub- 

 species, was originally the Behring Sea, after the Danish navigator Vitus 

 Behring (1680-1741). Subsequent authors emended Behringiana to 

 behringiana or beringianus, but Article 20 of the International Rules 

 stipulates that original spellings must be preserved. 



Dall (1914, p. 122) said, "F. islandicus Muller), extends from the 

 Arctic south in constantly deeper water to the Strait of Fuca. Varieties 

 of this were supposed to be P. rubidus Hinds by Middendorff, who did 

 not know the true rubidus [Martyn, 1784; = P. islandicus Muller], 

 and his name for one variety, beringiana, takes precedence of my variety 

 strategus, which is identical." 



As noted under Chlamys islandica (Muller), there are no valid 

 records for that species from south of the Bering Sea. 



The ribs of Chlamys islandica behringiana are quite variable. Those 

 of the right valve may be low and broadly-rounded fasciculi of five or 

 six ridges, or higher, narrower and dichotomous, dividing again near the 

 ventral margin. On the left valve they may be broadly-rounded fasciculi 

 with less prominent intercalaries, or narrow, distantly fasciculated and 

 with more prominent intercalaries. 



The differences in rib-structure and the smaller posterior auricles 

 are the principle criteria for separating this subspecies from the typical. 



Geographical range: Bering Sea; Gulf of Alaska, southward along 

 the Alaskan coast and off British Columbia, Canada. 



Geochronological range: Upper Pliocene, Pleistocene, Recent. 



Bathy metric range: No data available. 



Ecological data : None available. 



