413 Costa Rica Miocene — Olsson 241 



of California. This distribution on both sides of the Isthmus is 

 in harmony with its occurrence as a Miocene fossil. 

 Gatiin Stage: Port Limon. 



Antigona Blandiaiia Guppy Plate 30, figures 5, 6 



Venus Blandiana Guppy, 1874, Geol. Mag., London, Decade ii, vol. i, 



p. 436, pi. 17, fig. 6. 

 Cytherea ( Ventricola) Blandia7ia Dall, 1903, Trans. Wagner Free Inst. 



Sci., vol. 3, pt. 6, p. 1277. 

 Antigona ( Ventricola) Blandiana Maury, 1917, Bull. Amer. Pal., vol. 



5, p. 381, pi. 37, fig. 5. 



This species was described by Guppy from the Bowden beds 

 of Jamaica but also collected by the Maury expedition in the 

 Miocene of Santo Domingo. Dall also records it from the lower 

 Miocene of the Chipola beds and from Curacoa, Dutch West 

 Indies. It is a small species of nearly circular outlines and 

 sculptured with distant primary lamellae and finer secondary 

 threads in the interspaces. 



Our Costa Rican shells consist of two specimens, one from 

 the coral limestones near Port Limon, the other from the lower 

 Gatun of Comadre Creek near Cahuita. They differ from Dr. 

 Maury's specimens from Santo Domingo in having the primary 

 set of lamellae more distantly spaced and their interspaces more 

 closely striated with the secondary threads. 



Length 30, height 24, diameter 9 mm (left valves) Com- 

 adre. 

 Length 24, height 23, diameter 8.5 mm (left valve) Port 

 Limon. 

 Gattin Stage: Comadre creek, near Cahuita. 

 Port Lmion. 



Antigona Karrisiana, n. sp. Plate 30, figure 3 



Shell small, convex and nearly circular in outline; umbos 

 full with the beaks situated a short distance in front of the mid- 

 dle; lunule small but broadly cordate and sculptured with the 



