TRANSACTIONS OF WAGNER 



7O6 



TERTIARY FAUNA OF FLORIDA 



radially and the others concentrically threaded ; the left valve somewhat less 

 convex. Alt. 145, lat. 147, extreme length of hinge-line 80 mm. 



Pecten sp. San Pablo formation, Mount Diablo, Contra Costa County, 

 California, has fourteen to sixteen ribs, strong and simple, with narrower chan- 

 nelled interspaces, which, as well as the ribs in some cases, are radially striated; 

 ears subequal, somewhat impressed, with a few rather coarse radial riblets and 

 concentric striation. Alt. 127, lat. 137, hinge-line 70 mm. 



Pecten sp. A small species recalling P. descrti was collected near Mount 

 Diablo ; it is rounded, moderately convex, with eighteen to twenty slightly 

 nodulous subequal ribs, with channelled equal interspaces crossed by fine 

 looped concentric sculpture ; the shell is like a small teqttisulcatus in general 

 form, with small subequal ears. Alt. 28, lat. 28, hinge-line 18 mm. 



Pecten sp. indet. The flat valve of a species, in poor condition, but re- 

 calling P. dcntatus Sby., has been received from Miocene beds near San Diego. 



The following are of Pliocene age : 



Pecten (Patinopecten) expansus Dall. 



PLATE 26, FIGURE i. 

 Paten expansus Dall, Proc. U. S. Nat. Mus., i., p. 14, 1878. 



Pliocene of Pacific Beach (lower horizon), near San Diego, California ; 

 Hemphill, Dall, and Hamlin. 



Shell large, flattish, with, on the right valve, twenty-five to thirty flat 

 dichotomous ribs, which differentiate it from the other species of this group. 



Pecten (Pecten) Stearnsii Dall. 



PLATE 26, FIGURE 5. 



/'<( It-it Stt-arnsii Dall, op. fit., p. 15, 1878. 

 Found with P. expansus. 



This is the Pliocene precursor of Pecten diegcnsis Dall, from which it 

 differs by having five or six more ribs, which, in the adult, have a conspicuous 

 median sulcus. 



Pecten laqtieatus Sby., a Japanese species, has been erroneously cited by 

 Reeve from California. 



Pecten (Pecten) Hemphillii Dall. 



t'fftfii Hcmp/iHHi Dall, op. fit., p. 15, 1878. 



ini hi-lla ('.abb (non Conrad), Pal. Cal., ii., pi. 16, fig. 20, 1869; not /'. l>,-lla Sby., 

 nor /'. /v///.v McCoy. 



