TRANSACTIONS OF WAGNER 

 1260 



TERTIARY FAUNA OF FLORIDA 



This group is found in the Miocene, and in recent times has a more north- 

 ern distribution than Callocardia. Some of the peripheral species show an 

 approach to the dentition of species of Pitaria, but are retained here on the 

 basis of the other characters. 



Callocardia (Agriopoma) sincera n. sp. 

 PLATE 55, FIGURE 12. 



Oligocene of the Chipola horizon at Alum Bluff and on the Chipola River, 

 and probably at Ballast Point, Tampa Bay, in the silex beds. 



Shell small, short, ovate, very slightly rostrate behind, with low, pointed, 

 anteriorly directed beaks and a large lanceolate lunule defined by an incised 

 line ; surface finely, closely, concentrically wrinkled, with two obscure ridges 

 radiating from the beak behind, of which the anterior one forms a slight angle 

 where it intersects the base ; hinge solid, normal ; posterior right cardinal 

 bifid ; posterior dorsal margin deeply grooved to receive the bevelled edge of 

 the opposite valve ; pallial sinus short, angular, ascending. Length 20.75, 

 height 17.5, diameter 10.0 mm. 



This species, though much smaller and with the sculpture more clean-cut, 

 has the general features of C. Sayana, which succeeds it in the Miocene and of 

 which it may be regarded as the precursor. The slightly . pointed and rostrate 

 posterior end is peculiar to it. 



Callocardia (Agriopoma) gatunensis n. sp. 

 PLATE 54, FIGURE i. 



Oligocene of the Gatun beds near Gatun, on the line of the Panama Canal, 

 Rowell and Hill ; near the line of the railway at Monkey Hill, Newberry and 

 Hill ; at Ponton, St. Domingo, and at Clairemont, St. Ann's Parish, Jamaica, 

 West Indies. 



Shell moderately large, thin, inflated, ovate ; with low, incurved beaks over 

 a large, cordate lunule, defined by a feebly impressed line; ligament narrow, 

 the margins adjacent to it marked by a raised 'thread ; anterior dorsal slope 

 short, straight, the beaks being near the anterior fifth of the shell and the 

 margins raised above the general surface, where they cross the lunule ; anterior 

 end rounded, base evenly arcuate, posterior end broadly rounded, posterior 

 dorsal border moderately convex ; hinge delicate, anterior lateral small and 

 closely adjacent, posterior right cardinal bifid and rather widely separated from 

 the middle cardinal; pallial sinus ascending, linguiform, extending through 



