MIOCENE PECTENS. 93 



sp. On the ridge between the Upper and Lower Ojai Valleys, Ventura Cuuuty. 

 Mr. Eldridge has found P. lowpocetws with the following species, in beds which 

 he thinks are of lower Miocene (Vaqueros) age: Pecten cnissieardo, Turritella (qf.) 

 luyfmannl, PhmoldeH sp. (flat), (Mn-a sp., Numi sp., Dentqlium sp., Chione sp., 

 Leda sp. Balanus sp., Trifoniuni or Fnxu-^ sp. 



RANGE. 



Miocene (lower '.). Four miles south of Lonipoc, Santa Barbara County (F. M. 

 Anderson); ridge between upper and lower Ojai valleys. Ventura County 

 (Eldridge). 



Pectkx (lliNNiTES) cKiANTEUs dray. 



PI. XXIX, tiss. 1, 2, and 2. a 



1S26. Hinnites gigantCHx Gray, Ann. Phil., 2d s-er., vol. 12, 1826, p. lOS. 



1834. Hmnita poukoni C(yura.A, Jour. Acad. Nat. Sci., Phila., vol. 7, p. 182, pi. 14. 



1843. mnnUesgignnU-us Gray, Sowerby, Thes. Couch., vol. 1, Hinnites, p. 80, pi. 20, figs. 3-o. 



1853. Hinnites giganteus Grav, Reeve, Conch. Icon., vol. 8, Hinnites, Oct., 18.53, sp. 2, pi. 1, fii;. 3. 



1857. Himiite^ crassa Conrad, Pac. R. R. Rept., vol. 7, pt. 2, p. 190, pl._2, figs. 1 and 2. 



1863. Hinnites giganteus Gr&y, Carpenter, Brit. Assn. Rept., 1863, p. 645. 



1863. //mnte crassa Conrad, Carpenter, Brit. Assn. Rept., 1863, p. 595. 



1869. jETmrntes (/(sran(CT(s Grav, Gabb, Pal. Cal., vol. 2, 1869, p. 105. 



1887. Hinnites giganteus Grav, Whiteaves, Trans. Roy. Soc. Canada, vol. 4, sec. 4, 188,, p. 119. 



1S88. Pecten {Hinnites) giganteus Gray, Kiister, and Kobelt, Conch.-Cab., vol. 17, pt. 2, Spondylns und 



Pecten, sp. 228, taf. 65, figs. 9 and 10. 

 I.SSS. Hnnitesgigante.s Gr^y^Cooi^er, Seventh Ann. Rept. Cal. St. Min., 1888, p. 243 (^anta Rosa 



Island record excepted). 

 1,S92. Hinnites giganteus Gray, Keep, West Coast Shells, p. 165, fig. 138. 

 1892. Hinnites giganteus Grav, Williamson, Proc. U. S. Nat. Mus., vol. 15, 1892, p. 193. 

 1898. Hinnites giganteus Gray, Ball, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, 1898, p. ,11. 

 1898. Hinnites crassa Conrad, Ball, Trans. Wagner Free Inst. Sci., vol. 3, pt. 4, p. 711. 



1903. Pecten {Hinnites) giganteus Gray, Arnold, Mem. Cal. Acad. Sci., vol. 3, pt. 2, 1903, p. Uo. 



1904. Pecten {Hinnites) giganteus Gray, Keep, West American Shells, p. 42, fig. 22. 



Z>e.s«-i>?;»w(.— Shell averaging about 7.5 millimeters in altitude, usually not 

 quite so long its high, irregular, inequivalve. generally inequilateral on account of 

 attachment to irregular surface; shell quite thick; margins smooth. Right valve 

 more ventricose than left, ornamented by 9 to 18 narrow, irregular, pronnnently 

 squamose ribs, between which in the flat interspaces are less prominent raised lines 

 similarly sculptured; hinge lin.> more than one-half length of disk; ears subequal, 

 and more or less prominently sculptured by fine, squamo.se, radiatmg hues; l)yssal 

 sinus sometimes visible. Left valve less ventricose than right, otherwise similai-. 

 Hinge rather narrow and hetivy; fosset deeply excavated, oblique, narrow, and 

 anoular: hinge is dark purple in living shells. 



Dhne„siom.—AM. 7i» mm.: long. 65 mm.: hinge line 40 mm. ui length. Id lum. 

 in width; diameter I-!."! mm. 



The young of this species is free swimming until an altitude of about 20 or 30 

 millimeters is reached, when thev become attached to some fixed object. If this 

 object happens to have an irregular surface, tis is generally the case, the shell grows 

 irregular in consequence. The voung. up to the time of attachment, are indus- 



