4^3 



Costa Rica Miocene — OlSvSon 



251 



T. /in^ea Conrad, li diners irom csquistriata in its greater dor- 

 sal anterior slope and finer sculpture, and from T. lijitea of the 

 recent fauna, in its somewhat greater proportional height and 

 greater convexity. 



Gatun Stage: Coll. ^, Red Cliff creek. 



Section PHYLLODINA, Ball 



Tellina lepidota Dall Plate 26, figures 4, 5 



Tellina {Phyllodina) lepidota Dall, 1900, Trans. Wagner Free Inst. 

 Sci. , vol. 3, pt. 5, p. 1022, pi. 46, fig. 18. 



Ball's type of this species is based on a fragmentary right 

 valve from Gatun. We have several complete and large speci- 

 mens from Water Cay, where the species is fairly common. The 

 right valve is fiat and depressed, the left more convex. Both 

 valves are nearly similarly sculptured with 2 or 3 wide undul- 

 ations of the beaks, which are soon replaced by even, sharp, con- 

 centric lamellae, of which 3 or 4 are higher and more lamellose 

 on the dorsal margin. 



Length 24, height 12.5, diameter of the left valve 2.75 

 mm. 



Length 21.5, height 11.00, diameter of the right valve 

 1.25 mm. 



Gatun Stage: Water Cay. 



Section EURYTELLINA, Fischer 

 Tellina costaricana, n. sp. Plate 26, figures 6, 9 



Shell oblong, depressed; beaks small and inconspicuous 

 about the middle of the shell so that the anterior and posterior 

 ends are of nearly the same length; posterior end widely round- 

 ed the anterior but slightly narrowed and less round- 

 ed at its extremity; anterior and posterior dorsal margins nearly 

 straight; surface of the disk finely sculptured with even, con- 



