TRANSACTIONS OF WAGNER 



718 



TERTIARY FAUNA OF FLORIDA 



The Antillean species is quite distinct from that figured by Orbigny, and 

 more nearly resembles his P. tehuclchus, which has a more inflated and 

 rounder shell, with a much larger and less oblique posterior car. (Cf. Voy. 

 Am. Mer., Mollusques, pi. 85, figs. 21 to 24.) 



Pecten (Plagioctenium) demiurgus n. s. 



PLATE 26, FIGURE 3. 



Pfcti-n fomparilis Guppy, Geol. Mag., Dec. ii., vol. i., p. 451, 1874; not of Tuomey and 

 Holmes, 1855. (From types.) 



From the Caroni Series of Trinidad at Savanetta ; Guppy. 

 This species, which is closely related to the Pacific coast P. ventricostis 

 Sowerby, differs by its rounded and minutely squamose ribs, narrower um- 

 bones, wider and less inflated shell, with the anterior ears more deeply inset. 

 It has twenty ribs, smooth submargins, and a rather deep notch. Alt. 70, lat. 

 72, max. diam. 36 mm. The left valve is a little less inflated than the other. 



Pecten ritdis Gabb, as of Sowerby, from the Tertiary of Costa Rica, 

 appears to be indeterminable. 



Pecten (Pseudamusium) Guppyi n. s. 

 PLATE 34, FIGURES 12, 13. 



Oligocene of the Bowden marl, Jamaica, and of the Alum Bluff sand 

 at Oak Grove, Santa Rosa County, Florida, Burns; and in the Pliocene marl 

 of Port Limon, Costa Rica, Hill. 



Shell small, suborbicular, moderately convex, smooth, with the surface 

 covered with microscopic Camptonectes striation ; ears small, the anterior 

 slightly larger, all with very minute radiation and concentric lines ; notch 

 narrow, small, with no ctenolium ; interior smooth, without line or developed 

 crura; traces of the auricular crura alone perceptible; cardinal margin bearing 

 a sharply cross-striated, very distinct provinculum; basal margins flattened, 

 posterior margin slightly compressed. Alt. 6, lat. 6 mm. 



The abundance and uniformity of this little shell testify to its adult 

 character. Occasional individuals show a thickened line internally on each 

 side, on the lower edges of the submargins, like some recent species, and 

 also traces of coloration in blotches. 



Amusium papyraceum Gabb. 



J'/i-iiroiicctia papyracca Gabb, Geol. St. Dom., p. 257, 1873. 

 ? = Ann/sin in Mortoni Ravenel, 1844. 



Oligocene of Bowden, Jamaica, Henderson ; and of St. Domingo, Gabb. 



