no. 182.!. MOLLUSKS OF THE 0ENU8 CERITHIOPSIS— BARTSCH. 365 



Aperture suboval, decidedly channeled anteriorly; outer lip rendered 

 sinuous by the external sculpture; columella short, very broad, and 

 slightly expanded at the insertion, a little lighter in color than the 

 rest of the shell; provided with a strong callus on its inner edge which 

 is reflected over the parietal wall. 



The type (Cat. No. 74001, U.S.N.M.) was collected by Canfield at 

 Monterey, California. It has eight post-nuclear whorls and measures: 

 Length 4.2 mm., diameter 1.7 mm. A second immature specimen 

 (Cat. No. 23261, U.S.N.M.) is in the Stearns collection, also from 

 Monterey, California. 



CERITHIOPSIS PERUVIANA Orbigny. 



Plate 41, fig. 2. 



Cerithium peruvianum Orbigny, Voy. Amer. Merid., 1840, p. 443, pi. 77, figs. 9 

 and 10. 



Shell broadly elongate-conic, grayish-brown. Nuclear whorls 

 small, at least two. Post-nuclear whorls moderately rounded, orna- 

 mented with four nodulose, spiral cords, of which the first (which is at 

 the summit) is much smaller than the rest, the other three being 

 subequal. On the last two turns the first basal cord is apparent in 

 the suture. In addition to the spiral cords, the whorls are marked by 

 low, axial ribs, which are about as wide as the spiral cords. Of these 

 ribs, 12 occur upon the first and second, 14 upon the third, 18 upon the 

 fourth, and 22 upon the penultimate turn. The junctions of the 

 axial ribs and the spiral cords form well-developed tubercles. Sutures 

 moderately constricted. Periphery of the last whorl marked by a 

 feeble, tuberculated, spiral cord. Base slightly concave in the middle, 

 marked by five broad, low, rounded cords, which decrease regularly in 

 size from the periphery to the columella. Aperture rather large, irreg- 

 ularly oval, decidedly channeled anteriorly; posterior angle obtuse; 

 columella veiy stout, twisted, and reflected; parietal wall covered 

 with a thin callus. 



Orbigny's type came from the shore near Arica, Peru. It has 

 six post-nuclear whorls, and measures: Length 7 mm., diameter 2 mm. 



CERITHIOPSIS DESTRUGESI De Folin. 



Plate 41, fig. 6. 



Cerithium destrugesi De Folin, Le Meleagrinicoles, 1867, p. 71, pi. 6, fig. 12. 



Shell elongate-conic; early whorls yellow, the later ones darker. 

 Early post-nuclear whorls ornamented with four spiral keels, which 

 are much wider than the spaces that separate them. Of these, the 

 one at the summit and the third are of equal size and considerably 

 less strong than the other two, which are also equal. On the last six 

 turns the third cord becomes divided, the anterior portion being a 

 little stronger than its neighbor. In addition to the spiral sculpture 



