FAUNA OF ORTHAULAX PUGNAX ZONE. 29 



MICROCERION, new genus. 



Shell small, solid, few whorled, with one parietal and one pillar 

 tooth, a nodulous parietal callus uniting the lips, a thickened duplex 

 peritreme, both edges sharp, the posterior sharply reflected back- 

 ward, the inner or anterior projecting forward, externally beveled 

 to meet the bottom of the sinus between the two lips. 



Type. — Microcerion floridanus Dall, new species, Oligocene of the 

 silex beds of Tampa, Florida. 



This little shell stands about midway between Cerion proper and 

 the small Pui^idae. Nothing exactly corresponding to it is known 

 from other formations or from the recent fauna. 



MICROCERION FLORIDANUM, new species. 

 Plate 1, figs. 16, 17. 



Shell small, solid, stout, smooth, with about five whorls separated 

 by a distinct suture; nucleus smooth, rather blunt, hardly differen- 

 tiated from the subsequent rather convex whorls which are some- 

 what irregularly wound, the last whorl, at the suture, rising near the 

 aperture to the periphery of the penultimate whorl; base rounded, 

 imperforate, but which a chink behind the upper part of the pillar 

 lip; aperture rounded, the peritreme relatively thick, duplex, the 

 outer part wider, reflected, the inner part narrower, projecting for- 

 ward, the surface concentrically striated; parietal callus moderately 

 thick with a small nodulous projection near the junction with either 

 lip ; deeper in the throat is a single parietal nodule or denticle ; pillar 

 with a single deep-seated similar denticle; throat smooth. Height 

 4.75, maximum diameter 2.4 mm. 



Tampa silex beds, Ballast Point, Tampa Bay, Florida. 



Two specimens in the Post collection, U. S. Nat. Mus. No. 165018. 



Family PUPILLIDAE. 



Genus PUPOIDES Pfeiffer. 



Pupoides Pfeiffer, Malak. Blatt., vol. 1, p. 192, 1854 ; for BtiUmns nitidulus 



Pfeiffer, and B. fallax Say. 

 Lcucochila von Martens in Albers' Heliceen, 1860, p. 296. 

 Pupoides PiLSBRY, Proc. Acad. Nat. Sci. Phila., for 1900, p. 585. 



PUPOIDES PILSBRYI, new species. 



Plate 1, fig. 6. 



Shell small, rather pointed apically, with about five inflated whorls 

 separated by a distinctly marked suture; surface smooth except for 

 faint incremental lines ; last whorl longer than the spire, terminating 

 in a wide rounded-quadrate aperture with a widely reflected lip di- 



