20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



that separate them. These ribs extend strongly from the summit to 

 the periphery and render the suture wavy, while the impressed inter- 

 costal spaces also terminate their deep impression at the periphery. 

 The young specimen has 13 ribs on the last whorl and the adult cotype 

 bears 14. The suture is strongly constricted. The base is rather short 

 and well rounded. The aperture is obliquely subquadrate. 



The two cotypes, U.S.N.M. No. 561610, come from the Pliocene 

 deposits of North St. Petersburg, Fla. One has the nucleus and 11.5 

 whorls and measures: Length 6.6 mm., diameter 1.8 mm. The other 

 consists of the last 6.1 whorls, and measures: Length 6.2 mm., di- 

 ameter 2 mm. A young specimen is in the collections of the A.N.S.P. 



TURBONILLA (CHEMNITZIA) GERYONI, new species 

 Plate 3, figure 5 



Shell small, elongate-turrited, cream-yellow. The nucleus consists 

 of about 2.5 strongly rounded whorls that form a rather elevated 

 spire whose axis is at right angles to that of the postnuclear whorls, 

 in the first of which it is about one-third immersed. The nuclear 

 whorls are rather large and project somewhat beyond the outline of 

 the postnuclear spire on the left side. The postnuclear whorls are 

 strongly rounded and marked by very strong, somewhat rounded, 

 decidedly protractively slanting axial ribs. These ribs are of equal 

 strength from the summit of the whorls to their termination at the 

 periphery. The excavated intercostal spaces are narrower than the 

 ribs and also terminate at the periphery. Suture strongly impressed, 

 rendered somewhat wavy by the strong ribs at the summit of the 

 whorls. Of these ribs 15 are present on the last whorl of the type. 

 Periphery well rounded; base rather short, well rounded, without 

 sculpture. Aperture obliquely subquadrate. 



The type, U.S.N.M. No. 561611, comes from the Pliocene beds of 

 North St. Petersburg, Fla. It is a complete specimen, having 9 post- 

 nuclear whorls, and measures: Length 4 mm., diameter i.i mm. 



TURBONILLA (CHEMNITZIA) HIPPOLYTA, new species 



Plate 3, figures 4a, b 



Shell rather large, elongate-turrited, cream-yellow. The nucleus 

 consists of about 2.5 strongly rounded whorls that form a small 

 elevated spire whose axis is at right angles to that of the postnuclear 

 spire, in the first of which its last turn is slightly immersed. The post- 

 nuclear whorls are moderately rounded, marked by strong, somewhat 



