24 PROCEEDINGS OP THE NATIONAL MUSEUM Voi.. 70 



strong cord, which constitutes the termination of the axial ribs. 

 Base short and rounded, but concave at the junction with the 

 columella. The junction of the columella and the base is marked by 

 a slender spiral cord. Aperture broadly oval, decidedly channeled 

 anteriorly; posterior angle obtuse; outer lip thin, rendered sinuous 

 by the external sculpture, which is also seen within the aperture by 

 transmitted light; inner lip reflected over and appressed to the 

 columella. 



The type. Cat. No. 268746, U.S.N.M., was collected by George 

 Willett at Forrester Island, Alaska. It has nine postnuclear whorls 

 and measures, length, 7.5 mm. ; diameter, 2.5 mm. Two specimens 

 from the same collecting are registered as Cat. No. 366216, U.S.N.M. 

 Four additional specimens from the same station are in Mr. Willett's 

 collection. Another specimen. Cat. No. 340936, U.S.N.M., was col- 

 lected by Mrs. Oldroyd at San Juan Islands. 



This species suggests Cerithiopsis (Cerithiopsina) signa, but has 

 much larger nuclear whorls and is in every way more robust than 

 that species. 



CERITHIOPSIS (CERITHIOPSINA) SIGNA Bartsch 



Plate 5, fig. 4 



Cerithiopsis (Cerithiopsina) signa Bartsch, Proc. Biol. Soc. Wash., vol. 

 34, 1921, p. 36. 



Shell elongate-conic, pale brown. First half postnuclear whorl 

 smooth, the next one and a half well rounded and marked by rather 

 distantly spaced, almost vertical axial ribs. Postnuclear Avhorls ap- 

 pressed at the summit, marked by strong, rounded, almost vertical 

 axial ribs, of which 18 occur upon the first, 14 upon the second to 

 sixth, 16 upon the seventh, and 18 upon the last turn. The spiral 

 sculpture consists of three strong, equally spaced cords, which are 

 crossed by strong axial ribs. The intersection of the axial ribs and 

 the spiral cords foim strong tubercles, which are truncated on their 

 posterior margin and slope gently anteriorly in all three groups. 

 The spaces inclosed between the cords and the ribs are elongated pits 

 which have their long axis coinciding with the spiral sculpture. In 

 addition to this the entire surface of the spire is marked by fine 

 axial lines of growth and closely spaced spiral striations. Suture 

 strongly impressed. Periphery of the last whorl rendered angulated 

 by a keel. Base short, slightly concave at the insertion of the colu- 

 mella, marked by fine lines of growth and very fine spiral striations, 

 and a slender spiral thread at the insertion of the columella. Aper- 

 ture subquadrate; decidedly channeled anteriorly; posterior angle 

 obtuse; outer lip rendered sinuous by the spiral cords; inner lip 

 sigmoid, reflected over and appressed to the columella. 



