4ai Costa Rica Miocene — Olsson 249 



more convex than typical C. griis from the Carolinas and more 

 fineh- sculptured. More material is needed to show whether or 

 not these charaters are constant. The C. gnis appears as a 

 fossil in the Upper Chesapeake Miocene of the eastern United 

 States and is recent from Cape Hatteras to Yucatan. 

 Gatun Stage: Coll. /, Red Cliff creek. 



Genus TELLINA, (Linne) Lamarck 

 Teilina rovala, n. sp. Plate 26, figures 7, 8 



Shell elongate, slender, subequilateral with the beaks situ- 

 ated near the center of the shell; anterior side long, with a 

 straight dorsal margin and narrowlj^ rounded at its extremit}'; 

 posterior side much narrowed and rostrate, the left valve with 2 

 radial bands forming the rostrum, the dorsal one a fold, the oth- 

 er a wide sinus; ventral margin rounded anteriorly, nearly 

 straight about the middle and a wide sinus posteriorly; the sur- 

 face is sculptured with even, concentric lamellae; this sculpture 

 on the rostrum is heavier and on crossing the fold and sinus be- 

 come reversed in position. 



Length 29, height 12, semi-diameter 2.5 mm. 

 36 ? 14 3 mm. 



We have two specimens of this tj-pical Teilina from Water 

 Ca\-. The larger specimen is fragmentarj' but probablj' measur- 

 ed when complete about 36 mm in length. The species recalls 

 the recent West Indian T. interrupta Wood (7". a;?/c'«zy Philippi) 

 in its form and sculpture but lacks the finer radiating striae. 



Gatun Stage: Water Cay. 



Subgenus ARCOPAGIA. (Teach) 



Section MERISCA, Dall 

 Teilina crystaliina Wood Plate 26, figure 10 



Teilina crystallina Wood. 1S15, General Conchology. 



