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717 

 TERTIARY FAUNA OF FLORIDA ' ' 



perfect, covered with imbricating scales, those on the ribs triangular, apices 

 basally directed, and similarly on a smaller scale, on the threads, between the 

 keels and threads the imbrication is looped in an umbonal direction, sharp and 

 rasp-like ; ears subequal, with close, sharp, concentric, elevated lines and a few 

 subspinose radial threads ; interior grooved in harmony with the external ribs, 

 the margins of the channels reinforced by lirje in the adult; crura developed, 

 notch shallow. Alt. 47, lat. 46, diam. about 8 mm. 



This is quite a distinct species, not particularly like any other described 

 from this region and apparently a deep-water^ shell. The specimens in Gabb's 

 collection are mixed with others identified by him as oxygomim Sby., and their 

 horizon is not definitely settled. 



Pecten (Nodipecten) nodosus Linne. 

 Pcctcn iwdosus Linne (as Ostrcii), Syst. Nat., No. 164, 1758. 

 Pcctcn inagnificus Gabb, Geol. St. Dom., p. 256, 1873 ; from type, not of Sowerby, 1835. 



Oligocene of St. Domingo, Gabb (? Pliocene) ; Pliocene of Florida and 

 the Antilles, Willcox. Living in the Antillean region. 



The shell named iiiagnificns by Gabb is merely one of the less nodose 

 mutations of this well-known and variable species. 



Pecten (Plagioctenium) excentricus Gabb. 

 Pcctcn excentricus Gabb, Geol. St. Dom., p. 256, 1873. 



Oligocene of St. Domingo; Gabb and Bland. 



Shell small, oblique, with about twenty-one low ribs, narrow and flattened 

 on top, with subequal interspaces, both crossed by sharp, looped concentric 

 lamellae; submargins smooth, ears small, with sparse radial lines; auricular 

 crura pronounced, cardinal crura strong, with sharply incised cross-striation. 



This recalls a young specimen of siibvcntricosus. 



Pecten (Plagioctenium) G-abbi Dall. 

 Plate 29, Figure 3. 

 Pcctcn parancnsis Gabb, Journ. Acad. Nat. Sci. Phila., 2d Ser., viii., p. 347, pi. 45, fig. 24, 

 1881 ; not of Orb., Voy. Am. Mer. Pal., p. 135, pi. vii., figs. 5-9, 1849. 

 Oligocene of Antigua, Spencer ; and of St. Domingo, Gabb. 

 Shell broad, compressed, oblique, inequilateral, with nearly equal valves 

 and about nineteen concentrically scabrous, longitudinally striated ribs, with 

 narrower interspaces, each filled with one imbricated riblet. Alt. 48, lat. 52, 

 diam. 13 mm. 



