224 Bulletin 39 396 



iolana Maury of the Cercado formation of Santo Domingo but 

 the main difference lies in their dorsal areas, that of hispaniolana 

 Maury being sculptured more or less like the rest of the shell; 

 in bocasensis, as described above, the sculpture of the dorsal area 

 is dominantly concentric, only the upper half bearing 2 or 3, low- 

 but scabrous radials. 



Gatun Stage: Bocas del Toro. 



Subgenus PARVILUCINA, Ball 



Section BELLUCINA. Ball 



PSiacoides actinus Dall Plate 32, figure 24 



Phacoides {Bellucina) actinus Dall, 1903, Trans. Wagner Free Inst. 

 Sci., vol. 3, pt. 6, p. 1385, pi. 52, fig. 3. 



Ball gives for his typical specimens from the Bowden beds 

 of Jamaica, a height of 4.50 mm, while the Panama shells, all 

 from Bocas Island, do not exceed 3 mm in height but agree in 

 other respects. It is also recorded by Maury from the upper 

 part of the Cercado formation of Santo Bomingo. 



Gat2in Stage: Bocas del Toro. 



Genus DIVARICELLA, von Martens 



DivarJcella quadrisulcata d'Orbigny Plate 32, figure 20 



Lucina divaticafa Conrad, 1840, Fossils of the Medical Tertiary, p. 39, 



pi. 20, fig. 3, but not of I/inne. 

 Lucina quadrisulcata d'Orbigny, 1846, Voy. Am. Mer. , p. 584. 

 Divaricella quadrisulcata Dall, 1903, Trans. Wagner Free Inst. Sci. , 



vol. 3, pt. 6, p. 1389. 

 Lucina {Divaricella) quadrisulcata Bose, 1906, Boll, de Inst. Geol. de 



Mexico, numero 22, p. 77, pi. 11, figs. 2, 3. 



This species is ver}^ rare in Costa Rica. The shells are rath- 

 er thin and generally more finely sculptured and approach in 

 this respect the D. compsa Ball of the Florida Pliocene. Our 

 larges specimen measures: height 14 m, length 10 mm, diameter 



