no. 1820. NEW SHELLS FROM BERMUDA— DALL AND BARTSCH. 283 



by a sulcus as wide as that which separates the two spiral cords on 

 the spire, and like that crossed by the continuations of the axial ribs, 

 which extend to its posterior edge. Base moderately long, marked 

 by a slender spiral thread at the insertion of the columella, the space 

 between which and the peripheral cord appears as a broad, strongly 

 impressed spiral groove. Anterior half of the base marked by exceed- 

 ingly fine, incremental lines and spiral striations. Aperture irregular, 

 subquadrate, very strongly channeled anteriorly and feebly so at the 

 posterior angle, decidedly effuse at the junction of the outer and basal 

 lip. Outer lip thin, showing the external sculpture and color mark- 

 ings within ; inner lip slightly curved, reflected over the base ; parietal 

 wall covered with a thick callus which renders the peritreme complete. 

 Three specimens of this species (Cat. No. 221612, U.S.N.M.) were 

 received from Mr. Haycock, collected at Bermuda. All are lacking 

 the nucleus. The largest of these has six post-nuclear whorls and 

 measures: Length 2.3 mm., diameter 1.2 mm. The smallest, which 

 also has six post-nuclear whorls, measures: Length 2 mm., diameter 

 1 mm. 



CERITHIOPSIS PESA, new species. 

 Plate 35, fig. 10. 



Shell small, elongate-conic, banded as follows: Brown, excepting 

 the median row of tubercles and the depressed spaces on either side 

 of them, which are white. The dark tubercles on all the whorls are 

 a little lighter than the main portion of that part of the shell. 

 Nuclear whorls two and one-half, well rounded, smooth. Post-nuclear 

 whorls well rounded, marked from the very beginning by three spiral 

 cords, of which the first, winch is at the summit, is a little weaker 

 than the other two. The third is immediately above the periphery, 

 while the second is a little nearer to the first than to the third. In 

 addition to the spiral cords, the whorls are marked with almost verti- 

 cal axial ribs, which are almost as strong as the spiral cords. Of 

 these ribs, 16 occur upon the first to fourth, 18 upon the fifth, and 

 20 upon the penultimate turn. The junction of the axial ribs and 

 spiral cords form strong tubercles, of which those at the summit are 

 the smallest and well rounded; those on the median cord and basal 

 cord are truncated posteriorly, sloping gently anteriorly. The spaces 

 inclosed between the axial ribs and spiral cords are well impressed 

 squarish pits on the last whorls, while on the early whorls they are 

 rectangular pits having their long axes parallel to the spiral sculpture. 

 Sutures strongly impressed. Periphery of the last whorl marked by 

 a strong spiral keel, which is separated from the first suprasutural 

 keel by a groove almost as wide as that which separates the suprasu- 

 tural keel from its neighbor. The axial ribs extend partly upon the 

 peripheral keel and render it feebly tuberculous. Base somewhat 



