280 CEKION, GROUP XIV. 



C. TRIDENTATUM Pilsbry & Vanatta. PL 46, figs. 24, 25. 



Shell shortly rimate, moderately thick, strong, cylindrical, the 

 latter three whorls of about equal diameter, those preceding tapering 

 to form a long cone about, one-third the total length of shell. Chalky- 

 white, mottled with corneous, especially on the cone, rather polished, 

 the surface smooth except for slight growth-wrinkles, but a few whorls 

 following the two smooth, corneous nepionic ones are seen under a 

 strong lens to be densely striated, and the base of the last whorl has 

 irregular striae. Whorls 10, with just perceptible convexity, sutures 

 well marked below\ Last whorl ascending as usual. Aperture ovate, 

 about four-tenths the total length, much higher than wide, light 

 brown in the throat; peristome rather thin, narrowly reflexed, white; 

 columellar margin well reflexed ; parietal callus thin, its edge indis- 

 tinct, axial lamella small or inconspicuous from front aspect. Pari- 

 etal lamella small, short, central, with a still smaller accessory denti- 

 cle to the left of and beyond its inner termination, and another 

 slightly to the right and deeper within ; all visible without cutting 

 the shell. 



Length 271, <}j am . 19 ; apert., alt. 11, width 8| mill. 



Length 25, diam. 9 ; apert., alt. 10, width 1\ mill. 



Cuba (Robert Swift coll., A. N. S. P.). 



a. tridentatum P. & V., Proc. A. N. S., Phila., 1895, p. 206; 

 1896, pp. 326, 337, pi. 11, f. 27. 



This species superficially resembles closely C. incanum of Key 

 West, but differs in the ovate form of the aperture, sculpture of the 

 earlier whorls, and the teeth of the aperture. 



Subgenus EOSTROPHIA Ball, 1890. 



Shell wanting both parietal and axial lamellae. 



CERION ANODONTA (Ball). Trans. Wagner Free Inst. Sci., iii, 

 p. 13, pi. 1, figs. 8c, 8d. 



Oligocene: 'Silex Beds at Ballast Point and Old Tampa Bay, 

 west coast of Florida. 



CERION ANODONTA FLORIDANUM (Dall). L. c., fig. 6. 



Oligocene : Ballast Point. 



UNDESCRIBED OR UNRECOGNIZED SPECIES. 



Pupa striatella [Humphrey], Museum Calonnianum, p. 64 



