68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



The type, U.S.N.M. No. 561705, comes from the Pliocene of North 

 St. Petersburg, Fla. It has 7 postnuclear whorls and measures: 

 Length 3.5 mm., diameter 1.9 mm. An additional specimen is in the 

 collection of the A.N.S.P. 



This species is nearest related to Chrysallida macneili (below), 

 from which it can be readily distinguished by its much stouter outline. 



I take pleasure in naming this species for Dr. W. C. Mansfield, of 

 the United States Geological Survey, who did much work in Florida 

 Tertiary paleontology. 



CHRYSALLIDA MACNEILI, new species 

 Plate 15, figure 15 



Shell elongate-ovate, cream-yellow. The nucleus consists of about 

 2 rounded whorls, which form a depressed helicoid spire whose axis 

 is at right angles to the postnuclear spire, in the first whorl of which 

 the nucleus is half immersed. The postnuclear whorls are rather 

 high and almost flattened. They are crossed by very strong, almost 

 vertical axial ribs which are of the same strength from the summit 

 to the periphery. Of these ribs 11 are present upon the second, 13 

 upon the third, 16 upon the fourth, 18 upon the fifth, and 23 upon 

 the last whorl. The intercostal spaces are much narrower than the 

 ribs. The spiral sculpture consists of four cords, of which the first 

 at the summit is a little stronger than the rest and is a little more 

 distantly spaced from its neighbor than the subequal spaces that 

 separate the rest of the cords. The junction of the axial ribs and 

 spiral cords forms strong, slightly elongated nodules whose long axis 

 coincides with the spiral cords. The spaces enclosed by the axial ribs 

 and spiral cords are deep, almost round pits. The suture is only 

 slightly constricted and rendered wavy by the very strong tubercles 

 at the summit of the whorls. The periphery is marked by a weakly 

 nodulose spiral cord which is not quite so strong as the four above it. 

 The base is well rounded and marked by seven spiral cords and nu- 

 merous fine raised axial threads. Aperture elongate-oval, somewhat 

 effuse at the junction of the columella and basal lip; columella oblique, 

 thin and slightly reflected; parietal wall glazed by a thin callus; the 

 outer lip is gently curved and rendered slightly wavy by the external 

 spiral cords. 



The type, U.S.N.M. No. 561706, comes from the Pliocene of North 

 St. Petersburg, Fla. It has 7.5 postnuclear whorls and measures : 

 Length 4.0 mm., diameter 1.5 mm. 



