124 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



of the succeeding turns slightly rounded, ornamented with five 

 nodulose spiral cords, of which the first, at the summit, and the last, 

 at the periphery, are the widest, the three intermediate ones being 

 of about equal width. The spaces separating these spiral cords 

 are strongly incised, narrow channels. In addition to the spiral 

 cords, the whorls are marked by low, retractive, axial ribs, of which 

 67 occur upon the last turn. The junction of the axial ribs and the 

 spiral cords, form low, rounded, elongated tubercles, the long axis 

 of which corresponds with the axial sculpture. Base moderately 

 rounded, marked with low spiral cords, of which the two adjacent 

 to the umbilicus are about doubly as wide as the rest; the one 

 bordering the umbilicus renders the edge of this crenulated. In 

 addition to these spiral cords the base is marked by the continuation 

 of the axial ribs, the junction of which, with the spiral cords, renders 

 these nodulose. The nodules, on the two cords near the umbilicus 

 are elongate, having the long axis parallel with the spiral sculpture, 

 while those on the rest of the cords are more or less rounded. There 

 is a deep sinus between the peripheral cord and the basal cord, fully 

 twice as wide as any of the sulci on the rest of the spire. Two slender 

 spiral threads are present in the sulcus. The parietal wall of the 

 umbilicus is marked with two moderately strong spiral cords. Aper- 

 ture subcircular, rendered somewhat sinuous by the external sculp- 

 ture; columella very stout, provided with two low, rounded, spiral 

 cords which divide it into two equal parts. 



The type and another specimen, Cat. No. 249757, U.S.N.M., come 

 from Port Alfred (Coll. No. 1029). The type has almost four post- 

 nuclear whorls and measures: Greatest diameter, 9.6 mm.; lesser 

 diameter, 9 mm.; altitude, 4.6 mm. Cat. No. 186824, U.S.N.M., 

 contains two additional specimens from the same locality (Coll. No. 

 190). Cat. No. 249758, U.S.N.M., contains two specimens from the 

 same source (Coll. No. 1030). 



There is considerable variation in the width of the umbilicus of 

 this species, the following two having an umbilicus fully twice as 

 wide as the specimens alluded to above. In addition to this increased 

 width of umbilicus, they also have a little larger number of 

 axial riblets. Cat. No. 249756, U.S.N.M., one specimen from Port 

 Alfred (Coll. No. 1028). Cat. No. 186823, U.S.N.M., another speci- 

 men from the same place (Coll. No. 189). Cat. No. 250560a, U.S.N.M., 

 contains a very young tip of another specimen from the same place 

 (Coll. No. 1433a). 



HELIACUS LUTETTS Lamarck. 



Cat. No. 102725, U.S.N.M., a specimen from the Cape of Good 

 Hope. 



HELIACUS, species? 



Cat. No. 250502, U.S.N.M., contains a young Heliacus from Port 

 Alfred which is smooth, excepting a band at the periphery and two 



