64 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



Genus ACRILLA H. Adams. 



ACRILLA THALIA, new species. 

 Plate 17, figs. 5, 8. 



Shell elongate-conic, light brown, with a narrow white band on the 

 middle of each whorl. Nuclear whorls decollated. Postnuclear 

 whorls decidedly rounded, separated by a strongly constricted 

 suture, marked by well developed, very regular, almost vertical 

 axial ribs, of which 18 occur upon the first of the remaining turns; 

 20 upon the second; 22 upon the thud and fourth; 26 upon the fifth; 

 28 upon the sixth, and 34 upon the seventh and the penultimate 

 turn. These ribs are about one third as wide as the spaces that 

 separate them. Intercostal spaces marked by irregularly dis- 

 tributed, feebly incised, spiral striations. Periphery of the last 

 whorl well rounded; marked by a poorly developed spiral cord. 

 Base moderately rounded, marked by the continuations of the axial 

 ribs, and feebly incised, spiral striations. Aperture oval; outer lip 

 thin, showing the external markings within; inner lip decidedly 

 curved and reflected; parietal wall glazed with a thin callus. 



The type and another specimen, Cat. No. 186840, come from 

 Port Alfred (Coll. No. 207). The type has nine whorls remaining 

 and measures : Length, 33 mm. ; diameter, 8 mm. The other specimen 

 which has lost the nuclear whorls, having the nine succeeding turns, 

 measures: Length, 17 mm.; diameter, 4.3 mm. 



Genus GRAPHIS Jeffreys. 



GRAPHIS AFRICANA, new species. 

 Plate 36, fig. 10. 



Shell very minute, slender, elongate-conic, translucent. Nuclear 

 whorls a little more than two, somewhat inflated, ' smooth. Post- 

 nuclear whorls well rounded, appressed at the summit, marked by 

 almost vertical, somewhat sinuous axial riblets, of which 18 occur 

 upon the first, 22 upon the second and third, 24 upon the fourth and 

 fifth, and 26 upon the penultimate turn. These riblets are about 

 one-half as wide as the spaces that separate them. Intercostal 

 spaces crossed by slender spiral threads, of which about 15 occur 

 between the sutures on the later whorls. Periphery of the last 

 whorl well rounded. Base moderately prolonged, well rounded, 

 marked posteriorly by the feeble continuations of the axial ribs, 

 which vanish before crossing half of the base, and numerous, very 

 fine, incised, spiral striations. Aperture broadly oval; posterior angle 

 obtuse; outer lip thin, showing the external sculpture within; inner 

 lip thin and slightly reflected. 



The type, Cat. No. 249703, U.S.N.M., comes from Port Alfred 

 (Coll. No. 975). It has six and a half postnuclear whorls and 

 measures: Length, 2.3 mm.; diameter, 0.5 mm. Cat. No. 249708, 

 U.S.N .M. (Coll. No. 980), contains one specimen from Port Alfred. 



