TRANSACTIONS OF WAGNER 

 I 330 



00 TERTIARY FAUNA OF FLORIDA 



Gemma magna n. sp. 

 PLATE 57, FIGURE 4. 



Miocene of North Carolina at the Natural Well and Magnolia, Duplin 

 County ; Pliocene of South Carolina at Todd's Ferry, Waccamaw River ; of 

 Florida on the Caloosahatchie and Shell Creek; Pleistocene of North Creek, 

 near Osprey, Little Sarasota Bay, Florida. 



Shell trigonal, moderately convex, the anterior end slightly shorter, 

 rounded ; the posterior end longer, more pointed ; beaks high, pointed ; lunule 

 lightly flattened, bounded by an incised line often feeble, lanceolate, about half 

 as long as the anterior dorsal slope ; escutcheon not defined ; surface sculptured 

 with numerous regular, even, concentric sulci, with wider smooth interspaces ; 

 hinge normal, well developed, especially the long lateral laminae, the cardinals 

 entire ; basal margin crenulate, pallial sinus small, angular. Length 7, height 

 6, diameter 4 mm. 



G. magna attains a larger size than any of the later representatives of the 

 genus. It resembles G. var. purpurea of the recent fauna in its sculpture, but 

 relatively is much less inflated. 



Gemma magna variety virginiana Ball. 



Shell smaller, shorter, more delicate. Length 3.8, height 3.6, diameter 1.6 

 mm. 



From the Miocene of Yorktown, Virginia, in the middle portion of the 

 series ; Harris. 



This form is the earliest Gemma now known, and if I felt sure that it was 

 adult I should separate it specifically from G. magna, which appears in the 

 uppermost Miocene just before the opening of the Pliocene epoch. It closely 

 resembles the young of the G. magna, and perhaps larger specimens may here- 

 after turn up. 



Gemma trigona n. sp. 



PLATE 57, FIGURE 8. 



Miocene of North Carolina at the Natural Well and Magnolia, Duplin 

 County ; of South Carolina one mile east of Darlington ; Pliocene of South 

 Carolina at Todd's Ferry, on the Waccamaw River ; of Florida on the Caloosa- 

 hatchie River. 



Shell small, rather acutely trigonal, nearly equilateral ; beaks high, lunule 

 three-fourths as long as the dorsal slope ; surface smooth or with faint incre- 

 mental lines, or rarely a few concentric sulci visible near the ends of the valve 



