PAI,EONTOIX)GY ZORRITOS FORMATION 55 



differs in having five minor spiral threads instead of seven, 

 and in being distinctly larger. 



Lower Zorritos. Quebrada Zapotal. 



Family CYPRAEIDAE 

 Genus CYPRAEA Linnaeus 

 Cypraea angustirima n. sp. 



PLATE II Figs. 7, 8. 



Shell large, solid, with a narrow, closely denticulate aper- 

 ture and a somewhat flattened base. The aperture is prac- 

 tically straight anteriorly, and is curved posteriorly. The 

 inner lip is distinctly shorter than the outer lip at the pos- 

 terior canal, and the outer lip is produced dorsally, 

 heightening the contrast between the two sides of the canal 

 as viewed dorsally. The outer lip bears about 19 teeth, of 

 which the posterior three or four may be produced as slight 

 corrugations on the basal surface of the outer lip. The teeth 

 on the inner lip are strong anteriorly, obsolete posteriorly. 

 The dorsal surface is somewhat irregular; a pronounced 

 central hump marks the point of greatest convexity ; before 

 it the surface is evenly convex, and behind it a depressed 

 area slopes off to the aborted inner lip at the posterior canal ; 

 on the other side of the canal the outer lip rises prominently. 

 Length, 44; width, 32; height, 26.5 mm. 



This somewhat irregular, strong Cypraea is similar in 

 many ways to C. wilcoxii Dall, 49 from the Chipola beds of 

 Florida. It differs, however, in being fuller in width and 

 height, and in its peculiar shorter inner lip. C. henekeni 

 Sowerby, 50 from Santo Domingo and Gatun, is somewhat 

 similar, but differs in the tuberculate back apparently pecu- 

 liar to that species, as well as in its distinctly wider, more 



49 Trans. Wag. Inst, vol. 3, pt. i, p. 166, pi. 5, figs. I2b, c, 1890. 



50 Quart. Jour. Geol. Soc. Lond., vol. 6, p. 45, pi. 9, fig. 3, 1850 

 (as Cypraea henikeri}. 



