132 PROCEEDINGS OF THE NATIONAL MUSEUM vol.87 



horn-color and in having the angle of the whorls much more ante- 

 rior • that is, occupying not the middle but the anterior fourth of the 

 space between the summit and suture. 



STELLATOMA, new genus 



Shell small, elongate-ovate. Nuclear whorls with the first stage 

 smooth followed by a small area marked by slender, rather closely 

 spaced axial ribs, which merges into the postnuclear sculpture. The 

 postnuclear whorls have a broad sloping shoulder below the ap- 

 pressed summit that extends over about one-third of the whorls, 

 which is bounded anteriorly by an angle ; the anterior portion of the 

 whorls is greatly rounded. The whorls are marked by axial ribs, 

 which taper toward the summit and evanesce at the insertion of the 

 columella. The spiral sculpture on the early whorls consists of 

 rather strong cords, which weaken on the latter in some of the 

 species. Base marked like the spire. Columella short and stubby, 

 marked by spiral threads. Aperture elongate-ovate, decidedly chan- 

 neled anteriorly and at the posterior angle; outer lip much thick- 

 ened, marked by transverse striations and bearing a strong denticle 

 at the anterior termination of the posterior sinus; the inner lip also 

 bears a broad internal fold at the insertion of the columella. 



Type: Stellatoma steUata {Stea.rns) {^Mangelia stellata Stearns). 



Genus PYRGOCYTHARA Woodring 



PYRGOCYTHARA HEMPHILLI, new species 



Plate 17, Figube 2 



Shell small, elongate-ovate, varying in ground color from chestnut- 

 brown to wax yellow, usually with a pale zone at the angle of the 

 shoulder. The outer lip and base of the columella may be orange or 

 dark purplish orange. Nuclear whorls slender, the first 1.5 smooth, 

 succeeded by about two-tenths of a turn that shows slender, retrac- 

 tively curved, axial riblets, which in turn are followed by the post- 

 nuclear sculpture. Postnuclear whorls moderately well rounded, ap- 

 pressed at the summit. The postnuclear whorls are marked by very 

 strong, sinuous axial ribs, which taper at the summit and evanesce on 

 tne columella. Of these ribs 10 occur on the first and second, 9 on the 

 third and fourth, 10 on the fifth, and 9 on the last. In addition to the 

 axial ribs, the entire surface of tlie shell is marked by microscopic in- 

 cremental lines. The spiral sculpture consists of a low, rounded, ob- 

 solete keel, which occupies the middle of the turns on the first four 

 wJiorls but falls a little posterior to this on the rest of the shell. This 

 produces a decided shoulder on the whorls. Anterior to the shoulder 



