411 



COvSTA Rica Miocene — Olsson 



239 



two rows of incipient spines. In P. rosea there is only one row 

 of incipient spines and the dorsal-posterior area is smooth. 



This species is named for Miss Katherine Van Winkle of the 

 Paleontological Department of Cornell University and who is at 

 present engaged on a Monograph of the American species of 

 VeneridcB. 



Gahm Stage: Hill No. ^. Banana River, C. 

 Pitaria boucaryensis, n. sp. Plate 31, figure 10 



Shell rounded quadrate, thin and moderately convex; pos- 

 terior and anterior extremities rounded, umbos rather large; 

 lunule small and feebly defined by a faint, impressed line; sur- 

 face of disk sculptured with about 40 even, distant, concentric 

 lamellae; interspaces generally smooth or irregularly sculptured 

 with growth lines; interior of shell concealed. 



Length 31, height 22, diameter (right valve) 10 mm. 



As the single type specimen is fragmentary and imbedded 

 in a hard sandstone, the above measurements are but approxi- 

 mate. It is a very distinctive species, differing from the other 

 fossil Costa Rican Pitarias by its more delicate and convex shell 

 and more distant, even, concentric lamellae. 



Gatim Stage: Boiicary creek, C. R. 



Genus AMIGONA, Schumacher 



Antigona multscostata Sowerby Plate 30, figure I 



Venus multicostata Sowerby, 1835, Proc. Zool. Soc, p. 22. 

 Venus multicostata Reeve, 1863, Conch. Icon., vol. 11, pi. 3, fig. 9. 

 Cytherea {Cytherea) multicostata Dall, 1902, Proc. U. S. Nat. Mus., 

 vol. 26, p. 390. 



This is a large species living on the south or Pacific side of 

 the Isthmus. A perfect specimen was collected from the Gatun 

 beds of Water Cay, identical in every respect with recent ex- 

 amples from the Ba}^ of Panama. It is another instance among 

 the many which we have had occasion to note in the course of 



