XEW WEST COAST MOLLUSKS—BARTSCH. 



181 



neled at the junction of the short, thick, somewhat twisted columella 

 and outer lip. 



This description is based upon two specimens, cotj'pes, Cat. No. 

 1951!**;, U.S.N.M. One has the nucleus and 11 postnuclear whorls, 

 and has furnished the description of the nucleus. This measures: 

 Length 7.8 mm. ; diameter 2.8 nun. The other has lost its nucleus 

 and probably the first two postnuclear turns, and measures: Length 

 9 nun.: diameter 2.9 nnn. 



Speciiiinis in the U. S. National Museum. 



CERITHIOPSIS PEDROANA, new species. 



Shell small, slender, dark brown. Nuclear whorls three, 3'ellowish- 

 white, smooth. Post-nuclear whorls strongh' differentiated from the 

 nuclear ones, showing the sculpture characteristic of the adult shell 

 from the very beginning. This sculpture consists of three equally 

 spaced tuberculate spiral keels between the sutures, the posterior one 

 of which is slightly smaller than the other two. These keels are 

 separated by deep rounded channels almost as wide as the keel. In 

 addition tliere are many low, rather broad axial ribs, the intersec- 

 tions of which with the keel form the tubercles. About 20 of them 

 occur upon the; tirst, 22 upon the fifth, and 30 upon the penultimate 

 post-nuclear turn. The connection lietween the tubercles, both spiral 

 and axial, are about equal, inclosing deep, squarish pits. In addition 

 to the above sculy^ture the entire surface is marked by fine spiral lines 

 and lines of growth. Sutures strong!}' marked, constricted, showing 

 the peripheral keel in the later whorl. Periphery marked by a broad, 

 low. rounded keel. Another of equal width is located upon the middle 

 of the base. The sulcus which separates these keels and the supra- 

 peripheral sulcus are of equal width ; both are crossed by the weak 

 continuations of the axial ribs, which graduallv weaken as they pass 

 toward the columella. The basal keel is separated from the columella 

 by broad, shallow grooves. Aperture irregularly oval, decidedly 

 channeled anteriorly, outer lip thin, rendered sinuous by the external 

 keel; columella stout and somewhat twisted, with a strong callus on its 

 inner edge that extends over the parietal wall. 



