114 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



and are crossed by numerous slender, quite regular, and regularly 

 spaced axial riblets, which extend up on the sides of the spiral cords, 

 but do not cross their summit. In addition to these axial riblets, 

 the grooves between the cords are marked with many very fine, in- 

 cised, spiral lines. Sutures moderately constricted. Periphery of 

 the last turn angulated, the angle being formed by the fourth spiral 

 cord. Base short, well rounded, marked by two spiral grooves, one 

 of which forms the boundary for the anterior keel between the 

 sutures, and is crossed by slender axial riblets like the spiral grooves 

 on the spire, while the other, which is less strong, limits the columella. 

 The space between these two grooves is crossed by numerous, fine, 

 spiral striatums and incremental lines. Aperture moderately large, 

 subquadrate, decidedly channeled anteriorly. Posterior angle very 

 obtuse; outer lip thick, rendered sinuous by the external spiral cords; 

 columella short, strongly curved, and slightly reflected over the rein- 

 forcing base; parietal wall glazed with a moderately strong callus. 



There are eight specimens of this species in the United States Na- 

 tional Museum. Cat. No. 1S6802, collected at Port Alfred (Coll. No. 

 167). Two of these have served as cotypes, one having nuclear 

 characters and the other showing the adult structures. Our figure 

 is a composite one built upon these two specimens. The smaller of 

 these two specimens has ten postnuclear whorls, and measures: 

 Length, 8.5 mm.; diameter, 2.5 mm. The adult specimen, having 

 lost the nuclear and the early whorls, has 10 whorls remaining, which 

 measure: Length, 10 mm.; diameter, 3.1 mm. 



SEILA AFRICANA, new species. 

 Plate 17, fig. 6. 



Shell regularly elongate-conic, chestnut brown, a little lighter on 

 the early whorls. (Nuclear whorls decollated) . Postnuclear whorls 

 flattened, marked with strong flattened spiral keels, of which three 

 occur upon all the whorls between the sutures. The first of these 

 is a little anterior to the summit, leaving a somewhat concave shoulder 

 at the summit; the last is an equal distance above the suture; while 

 the second is midway between the two. These keels are separated 

 by deep, concave grooves which are a little wider than the keels. 

 In addition to these spiral keels, the whorls are marked by exceed- 

 ingly fine, closely-spaced, axial, raised threads, which cross the 

 deep grooves that separate the spiral keels, the sutures appearing 

 like the grooves on the whorl. On the last three whorls the summit 

 of the turns falls slightly anterior to the peripheral cord, which shows 

 partly in the suture. Periphery of the last whorl decidedly angu- 

 lated, marked by a cord a little less strong than those occurring upon 

 the spire. Base moderately long, well rounded, marked by two 

 spiral cords, of which the first is about as far anterior to the peripheral 



