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707 



TERTIARY FAUNA OF FLORIDA ' 



Found with P. expanses. 



This shell is probably identical with the Janira bclla of Gabb, but it 

 differs from the original J. bclla Conrad by its entire ribs, rounded above 

 instead of square, with extremely fine concentric lamellation. 



Pecten (Peoten) compaotus n. s. 

 Plate 34, Figure 5. 



Pliocene of Ventura County, California, at an elevation of two hundred 

 feet and eight miles inland from the sea; U. S. Nat. Mus., No. 61,246. 



Shell having a general resemblance to Pecten dentatus Sby. and P. 

 Poiilsoni Morton, being slightly larger than the latter and sculptured more 

 like the former. Right valve with twenty flat-topped, entire, smooth, squarish 

 ribs, separated by much narrower channelled interspaces, crossed by faint 

 incremental lines; submargins smooth except for incremental lines; posterior 

 ear with six or seven faint minute radials crossed by elevated lines of growth ; 

 byssal ear small, with three or four conspicuous subimbricate radials and a 

 rather small notch and ctenolium ; internal basal margin fluted ; hinge-teeth 

 rather strong. Alt. 27, lat. 27, diam. of left valve 8 mm. 



Pecten (Plagioctenium) subventricosus n. s. 

 Plate 29, Figure S. 

 Pliocene of Ventura County, California, Bowers ; and of Pacific Beach at 

 San Diego, Stearns and Hemphill. 



Shell of the type of P. veiitricosiis Sby., from which it differs by being 

 smaller and less tumid, less expanded laterally, with the ribs rounded, instead 

 of flattened, above, and with narrower interspaces ; the tops of the ribs 

 smooth, the sides with a dense fringe of concentric lamellae, much as in cont- 

 paiilis T. and H. Alt. and lat. 65, diam. 24 nmi. 



Pecten (Clilamys) opuntia n. s. 

 Plate 29, Figure 6. 

 Pliocene of San Diego, California ; Hemphill and Hamlin. 

 Allied to P. hericeits var. navarclius Dall, from which it differs by its 

 smaller and not fasciculated radial ribs, more elongated anterior ear, more 

 densely radially costate posterior ear, small size when adult, and by a tendency 

 to be suddenly contracted at the basal margin on the completion of growth, 

 somewhat as in P. pesfelis. Alt. 35, lat. 32.5 mm. 



