FREE INSTITUTE OF SCIENCE 



987 



TERTIARY FAUNA OF FLORIDA ^ ' 



near the base, the posterior flexure feeble ; escutcheon long and narrow, lunule 

 wider, elongate, both chiefly impressed on the dorsal edge of the left valve ; 

 sculpture of regularly spaced, numerous low, sharp, thin concentric lamellae, 

 with wider, microscopically radially striate interspaces ; there are about fifteen 

 lamellae to the centimeter; hinge and other internal characters normal. Alt. 

 46, lat. 54, diam. 21 mm. 



This fine shell is not unlike the Pliocene 6". Leana, but the sculpture in the 

 latter is coarser and more prominent and the valves thinner and flatter. 



Semele silicata n. sp. 

 Plate 38, Figure 6. 



Oligocene silex beds at Ballast Point, Tampa Bay, Florida ; Dall. 



Shell small, moderately convex, inequilateral, with low beaks ; anterior end 

 longer, evenly rounded from the Itmular slope ; posterior end shorter, higher, 

 hardly folded ; sculpture of numerous close-set, rounded, little elevated, con- 

 centric threads, separated b}' narrower grooves with no indication of radial 

 striation ; lunule and escutcheon very narrow, teeth rather strong. Alt. 20, 

 lat. 23, diam. 8 mm. 



The figure was taken from a siliceous pseudo-morph on which the sculpture 

 was indistinct. Subseqiiently other specimens showing the sculptLire better were 

 obtained. It is not unlike that of 6". suhovata Say, var. duplinensis, but the 

 threads are finer, closer, and more numerous. 



Semele Smlthii n. sp. 

 Plate 43, Figure 6. 



Upper Oligocene of the Chipola horizon at McClellan's farm, Calhoun 

 County, Florida ; Burns. 



Shell small, slightly inequilateral, thick, solid, the valves moderately convex, 

 with a perceptible posterior fold; beaks low, small; lunule and escutcheon 

 narrow ; anterior end slightly longer, sloping above, rounded in front and on 

 the base ; posterior end higher, rounded, scarcely truncate below ; sculpture of 

 hardly perceptible incremental lines and obscure sparse radial striations, imper- 

 ceptible on some parts of the shell ; teeth well developed ; pallial sinus obliquely 

 ascending, rounded in front and rather shorter than usual. Alt. 19, lat. 23, 

 diam. 7 mm. 



Fragments of two valves were obtained of this interesting nearly smooth 

 species, which is named in honor of Professor Eugene A. Smith, State Geologist 

 of Alabama, whose valuable work on the geology of the Southern States is well 

 known. 



