NO. 2 PYRAMIDELLID MOLLUSKS — BARTSCH 47 



St. Petersburg, Fla. It has 8.2 postnuclear whorls and measures: 

 Length 4.4 mm., diameter i.i mm. U.S.N.M. No. 561647 has two 

 additional specimens from the same source and two more are in the 

 collection of the A.N.S.P. 



The strongly rounded whorls and strong, broad axial ribs will 

 easily distinguish this from the other seven spirally pitted species. 



PYRGISCUS DIANAE, new species 

 Plate 9, figures 2a, b 



Shell small, turrited, stout, broadly elongate-conic, cream-yellow. 

 Nuclear whorls 2.5, strongly rounded, forming a rather elevated 

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

 whorls, in the first of which it is about one- fourth immersed. The 

 postnuclear whorls are flattened and crossed by retractively slanting 

 axial ribs, which are poorly developed on the first two turns, beyond 

 which they become stronger on successive whorls. Of these ribs, 14 

 are present upon the third, 16 upon the fourth to sixth, 18 upon the 

 seventh, and 21 upon the last turn. They are of the same strength 

 from the summit to the periphery. The intercostal spaces are about 

 as wide as the ribs; they are crossed by seven spiral pits, of which 

 the third is much wider than the rest which are of subequal strength ; 

 for spacing of these pits see detailed sketch, plate 9, figure 2b. Suture 

 moderately strongly impressed, rendered wavy by the summit of the 

 axial ribs. Base rather short, hemispherical, smooth. Aperture sub- 

 quadrate, columella short, with a small oblique fold a little below its 

 insertion, outer lip strongly curved, parietal wall with a moderately 

 strong callus. 



The type, U.S.N.M. No. 561648, comes from the Pliocene of North 

 St. Petersburg, Fla. It has 8 postnuclear whorls and measures: 

 Length 3.6 mm., diameter i.i mm. 



The more conic outline, less strong axial ribs, and flattened whorls 

 will readily distinguish this species from Pyrgiscus apolloi (p. 46) . 



PYRGISCUS LATONAE, new species 



Plate 9, figures la, b 



Shell moderately large, turrited, cream-yellow. The nucleus con- 

 sists of 2 small, strongly rounded whorls, which form a well-elevated 

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

 whorls, in the first of which it is about one-fourth immersed. The 

 postnuclear whorls are almost flattened and crossed by strong re- 



