50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



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

 postnuclear whorls. The postnuclear whorls are marked by very 

 strong vertical axial ribs except for the first turn, which is smooth. 

 Of these ribs i6 are present upon the second and third, 17 upon the 

 fourth to seventh, and 18 upon the last whorl. The intercostal spaces 

 are about as wide as the axial ribs and are marked by seven spiral 

 pits which vary greatly in width and spacing and are best described by 

 our sketch, plate 9, figure 6b. Suture moderately constricted, rendered 

 wavy by the summit of the axial ribs. Base hemispherical, smooth. 

 Aperture obliquely oval, columela slender, curved and provided with 

 an oblique fold a little below its insertion ; outer lip thin. 



The type, U.S.N.M. No. 561655, comes from the Pliocene of North 

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

 Length 3.8 mm., diameter i mm. U.S.N.M. No. 561656 contains two 

 specimens from the same source, and two more are in the collection 

 of the A.N.S.P. 



The vertical axial ribs and detailed spiral sculpture readily dis- 

 tinguish this species from Pyrgiscus harmoniae (p. 49). 



PYRGISCUS INOAE, new species 

 Plate 9, figures 5a, b 



Shell moderately large, turrited, shouldered near the summit, cream- 

 colored. Nuclear whorls 2, strongly rounded, forming a depressed 

 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 have the space between the second and third spiral 

 pit elevated into a spiral cord, which lends to the whorls the shoul- 

 dered appearance. The postnuclear whorls are crossed by strong axial 

 ribs of which 12 are present upon the first, 14 upon the second and 

 third, 16 upon the fourth and fifth, 18 upon the sixth and seventh, 

 and 24 upon the last whorl. These ribs are equally strong from the 

 summit to the periphery and show conspicuously the hump between 

 the second and third spiral pit. The intercostal spaces are about as 

 wide as the ribs and are crossed by eight spiral pits which differ 

 greatly in size and spacing and are best described by our detailed 

 sketch, plate 9, figure 5b. The suture is only moderately impressed 

 and rendered wavy by the summit of the axial ribs. The base is rather 

 short, rounded, and smooth. The basal part of the aperture is broken 

 but it is probably subquadrate; the columella bears a strong oblique 

 fold a little below its insertion. 



The type, U.S.N.M. No. 561657, comes from the Pliocene of North 



