112 TERTIARY AND QUATERNARY PECTENS OF CALIFORNIA. 



lines; byssal notch prominent; posterior ear small and with radials and imbricating 

 concentric sculpture. Left valve with small, obscureh' fasciculated, imbricated ribs, 

 each fascicule havinu- one major and several nuich smaller and more prominently 

 imbricated ril)lets; interspaces very nari'ow and sculptured as in right valve; ears 

 similar to those of right valve except lacking notch in anterior one. Color piidv to 

 white, the left valve being the darker. 



D'niiifnuonx. — Alt. 58 mm.; long. .5" mm.; hinge line 29 mm.; diameter 18 mm. 



Doctor Dall. in mentioning this variety, says:" "The typical specimens seem 

 remarkably distinct from /'. hericeus var. lutrarchiix^ but in a large series intergra- 

 dation is obvious." Carpenter in his original description mentions that var. hhidsi! 

 "passes from ImstatHs towai'd /f:/<ni(//ciix." 



Living. Bering Sea to Monterey (l>all); Victoria, B. C. (Button); Quatsino Sound 



and vicinity of Vancouver Island (Dawson; Whiteaves). 

 Pleistocene. Sucia Island, Puget Sound (Tsewcond)e). 



Pliocene. Deadmun Island, near San Pedro (.\riiold). 



■ 



Pecten hastatus Sowerby var. navakchus Dall. 

 PI. XLIII, liirs. I, Ir,. Mii.l 1/.. 



1844. Pecku ruhidan Hinds, Zool. Voy. Sulph.. 1S44, ji. til, \A. 17, tig. 5 (not P. nihidiif ilartyn, 



1784). 

 1898. Pecten hericeus var. vdrarclni.i Dall, Trans. Wagner Free Inst. Sci., vol. 3, j)t. 4, 1898, p. 708. 

 1904. Pecten rnbidus Hinds, Keep, West Am. Shells, p. 40. 



Description. — Shell averaging about 55 millimeters in altitude, higher than 

 long, subequivalve, l)oth valves only slightly ventricose. thin, sides only slightly 

 concave above. Right valve light colored, less venti'icose than left, with numerous 

 small, subangular, fiat-topped, dichotomous, and slightly imbricated ribs; surface 

 obscui'cly tessellated; anterior ear (juite prominent, with about 6 prominent 

 radiating ridges and numerous imbricating incremental lines; byssal notch of 

 medium size; posterior ear small, with distinct radial ridges and imbricating 

 sculpture. Left valve reddish or pinkish, more ventricose than right, with 

 nmnerous small fast'iculated and ([uite prominently imbricated ril)s, each fascicule 

 having one prominent rib in the middle with lesser ones on the sides; the niajoi' 

 interspaces occupied by a small riblet; ears as in right valve except lacking 

 byssal notch. Margins not prominently serrate. 



I)ii)i( Hxioiis. — Alt. 55.5 mm.: lon<>-. 54 nun.: hinge line "21 nun.: diameter 

 IT mm. 



This variety is smaller and more delicate than /'. !slan(licui<, and has fast'icu- 

 lated rather than tlichotomous ribs on the left valve. 



Living. Aleutian Islands southward to Lower California (Dall); Kodiak Island. 

 Alaska (Greelej' and Snodgrass). 



" Op. cit.. p. 709. 



