134 GEOLOGY AND PALEONTOLOGY OF THE WEST INDIES. 



Pecten vaughani var. flabellum, new variety. 

 (Plate 8, Figures 6 a, b, 7.) 



The following is a description of this variety: 



Shell small, equivalve, depressed, polished, with 15 round, radiating ribs, 

 rarely extending to the beaks, separated by equal concave interspaces; sub- 

 margins narrow, smooth, convex, usually separated from the body of the shell 

 by an angulation; concentric sculpture of close, fine growth-lines, usually 

 obliterated; ears large, subequal; posterior ears smooth except for fine growth- 

 lines; left anterior ear with obscure radiating riblets, right anterior ear with 

 about 6 strong scabrous riblets; byssal notch about one-half the length of the 

 ear; interior of the disk grooved in accordance with the ribbing. 



Alt., 22 mm.; lat., 22 mm.; diameter of joined valves, about 7 mm. 



Pecten vaughani closely resembles this variety, but is usually a little 

 smaller, the ribs are narrower and generally extend to the beak, and 

 the submargins are flatter and more acutely angulated than those of 

 the Cuban form. In general appearance typical Pecten vaughani is 

 neater and more clean-cut than the variety flabellum. 



Localities. — La Cruz and Santiago, Cuba, stations 3192, 3439, 3441, 

 3446, and 5255 (types) ; Vaughan, Black. 



Geologic horizon. — Oligocene. 



Type.— U. S. Nat. Mus. No. 167089. 



Pecten gardnerae, new species. 

 (Plate 7, Figures 5, 6.) 



The following is a description of this species : 



Right valve inflated, with 15 round ribs a little wider than the interspaces; 

 submargins slightly convex, steep; anterior ear with about 6 radiating riblets, 

 byssal notch one-half the length of the ear; posterior ear large, nearly rect- 

 angular; sculpture of close, minute growth-lines over entire shell. 



Alt. of right valve, 21 mm.; lat., 21.5 mm. 



Left valve flatter, with about 16 even, rounded ribs a little narrower than 

 the interspaces; submargins convex, steep; anterior ear acutely oblique, with 

 two or three very faint, broad, radiating riblets; posterior ear rectangular; 

 concentric sculpture of minute, elevated, very close-set lines extending over 

 entire shell, but on the disk grouped into bands or growth stages about 0.3 

 mm. wide. 



Alt. of left valve, 22.6 mm.; lat., 22.3 mm. 



The right valve is much more convex and appears less spreading 

 than the left, and the concentric sculpture is much less distinct. This 

 last feature is probably due to the better state of preservation of the 

 left valve. I have described the valves separately on account of the 

 possibility that they may belong to different species. 



Pecten gardnerm has closer, higher, and more strongly convex ribs 

 than P. vaughani and the ribs, in the specimens at hand, extend to the 

 beaks. The secondary sculpture is very different. 



