MIOCENE PECTENS. 77 



Dimensiorif!. — Alt. (1:^ luin.; long. 72 mm.; hinge line iu nnu. ; diameter 12 nmi. 



This species is similar in general characteristics to the typical P. estreJlanm, 

 hut differs from it in being much ilatter, having' a relatively much longer hinge, 

 and, on the average, more ribs. The characteristic constriction of P. estreUanus 

 is also lacking- in this variety, so far as known. 



P. var. cafalimt ranges from the upper Miocene to the Pliocene. On Santa 

 Catalina Island it is associated with the typical P. estfellauiut, in beds which are 

 probably upper Miocene, while at Temescal Canyon, near Santa Monica, it is 

 associated with the well-known Pliocene species P. stearnsn^ P. cerrosmisis, and 

 Laqueus ccdlfurnicus [ov Jeffrey xi). 



The t3^pe, which is figured and is now in the collection of Delos Arnold, was 

 found in a limy nuitiix near the isthmus, Santa Catalina Island, Los Angeles 

 County, by Mr. F. H. Thurston. 



RANGE. 



Pliocene (lower). Temescal Canyon, Santa Monica Mountains, Los Angeles County 



(Watts). 

 Miocene (upper). Isthmus. Santa Catalina Island, Los Angeles County (Thurston, 



Mrs. Trask);^ San Ardo and vicinity, Monterey County (Hamlin, Anderson). 



Pecten (Lykopecten) estrellanus CONRAD var. TERMINUS n. var. 

 PI. XXIII, tiers. 2 and 2.1. 



Descriptioi). — Shell averaging about 70 millimeters in altitude, somewhat longer 

 tiian high, ventricose, subcquivalve, equilateral; margins coarsel_y serrate. Right 

 valve with about l.> prominent, squarish ribs, separated by narrower channeled 

 interspaces, in each of which runs a prominent intercalary; surface of ribs and 

 interspaces obsoletely radially striate; hinge line more than one-half length of disk; 

 ears subequal, the anterior strongly radially ribbed, the posterior with finer 

 sculpture: byssal notch deep and rather narrow. Left valve similar to right, except 

 that the ribs are relatively narrower. 



Dimensumii. — Alt. "omm.; long. 75 nun.; hinge line 43 mm.; diameter 32 mm. 



This variety is distinguishable from the typical form by its fewer and broader 

 ribs, relatively longer hing<^ line, and finer obsolete radial striation; and from var. 

 catalinix by its fewer ribs and greater convt>xity. 



The type of P. var. temunux is fi'om tiie upper Miocene or Sun Pablo horizon 

 of Montere}' County, and is now in the collection of the University of California. 



RANGE. 



Miocene (upper). Monterey County (University of California). 



Pecten (Lyropecten) magnolia Conrad. 



PI. XXIV, tigs. 1 and 2; PI. XXV, tig. 1. 



18.57. Peclen magnoVui Conrad, Pac. R. R. Rept., vol. 7, 1857, p. 191, pi. 1, tig. 2. 



1888. Liropecten veat'chii Cooper (not of (jabb). Seventh Ann. Rejit. t'al. St. Min., 1888, p. 246 



("Pliocene, Ojai Valley"). 

 1898. Pecten magnolia Conrad, Dall, Tran*. Wagner Free Inst. Bci., vol. 3, pt. 4, 1898, p. 702 (in part). 

 1901. Pecten magnolia Dall, Nautilus, vol. 14, 1901, p. 117 (in part.) 



