397 Costa Rica Miocene — Olsson 225 



of left valve 4.50 mm. The D. prevaricata Guppy of the Mio- 

 cene of Santo Domingo and Jamaica measures only 8 mm in 

 height. 



The D. quadrisulcata is a recent species of the West Indies 

 appearing in the east coast Miocene of the United States for the 

 first time in the Upper Chesapeake. 



Gatun Stage: Coll. 4., 5, Red Cliff creek. 

 Middle creek. 



Genus CARDIUM, Linne 

 Subgenus TRACHYCARDIUM, Moerch 



Cardium Stiriatum Brown and Pilsbry Plate 27, figures 4, 5 



Cardiuni {Trachycardinnt) stiriatum Brown and Pilsbry, 191 1, Proc. 

 Acad. Nat. Sci. Phila., vol. 63, p. 366, pi. 28, fig. 11. 



This is most elegant of the several species of Cardium in 

 the Miocene of Panama and Costa Rica. The shell is high and 

 inflated with about 30 radial ribs which are peculiarly sculptur- 

 ed with twisted or obliquely projecting tuberclers placed on the 

 posterior side of the ribs and overhanging the adjacent inter- 

 space. Large specimens may reach a height 50 mm. It is re- 

 lated to the recent West Coast Cardiuni belcheri Broderip. 



Gatun Stage: Gattin^ C. Z. 



Water Cay, Panama. 

 Hill No. I , Banajia River. 



Cardium dominicense Gabb Plate 27, figure 2 



Cardium ) Trachycarditim) dominicense Gabb, 1873, Trans. Amer. 

 Phil. Soc, vol. 15, p. 25. 



Cardium, {Trachycarditim^ dominicense Qabh, 1881, Journ. Acad. Nat. 

 Sci. Phila. , 2nd series, vol. 8, p. 344. 



Cardium [Trachy cardium) gatunensis Toula, 1908, Jahrb. der K-K 

 Geol. Reichsanstalt Wien, vol. 58, p. 720, pi. 27, fig. 4. Not Card- 

 ium {Fragum) gatunensis DaW, 1900. 



