342 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 40. 



CERITHIOPSIS (CERITHIOPSIS) STEJNEGERI Dall. 

 Plate 40, fig. 3. 

 Cerithiopsis stejnegeri Dall, Proc. U. S. Nat. Mus., vol. 7, 1884, pp. 345-346, pi. 2, fig. 4. 



Shell broadly conic, light chestnut brown, excepting the nucleus 

 and the columella. Nuclear whorls two, strongly rounded, smooth. 

 Post-nuclear whorls well rounded, marked with three nodulose 

 spiral keels, of which one is at the shouldered summit, another some- 

 what posterior to the suture, while the third is median between the 

 two. The anterior of the three is the stronger and the one at the 

 summit the weakest. These cords are about as wide as the spaces 

 that separate them. In addition to the spiral cords the whorls are 

 marked by very poorly developed, almost vertical axial riblets, the 

 junctions of which with the spiral cords form the nodules. Of these 

 ribs 16 occur upon the second, 18 upon the third, 22 upon the fourth, 

 24 upon the fifth, and 26 upon the penultimate whorl. The spaces 

 inclosed between the spiral cords and axial ribs are irregular, shallow, 

 impressed, rounded pits. Sutures strongly constricted, showing the 

 posterior edge of the base. Periphery of the last whorl marked 

 by a sulcus which is crossed by the feeble axial riblets; base well 

 rounded, smooth, excepting incremental lines. Aperture broadly 

 ovate; decidedly channeled anteriorly; posterior angle obtuse; outer 

 lip thin, rendered wavy by the external sculpture showing the external 

 sculpture within; columella short, stout, twisted, and curved; parietal 

 wall glazed with a thin callus which extends from the inner edge of 

 the columella to the posterior angle of the aperture. 



The type (Cat. No. 40932, U.S.N.M.) was collected by Dr. L. 

 Stejneger at Bering Island. It has eight post-nuclear whorls, having 

 lost the nuclear turns and measures: Length 5.5 mm., diameter 2.2 

 mm. The nuclear whorls were described from a specimen of Cat. 



No. 195172, U.S.N.M. 



Specimens examined. 



U.S.N.M. 

 Cat. No. 



Locality. 



Number of 

 specimens. 



i 40932 

 161049 

 195172 

 130625 

 195174 

 161108 

 161036 

 195173 



Bering Island 



Kyska Uarbor, Aleutian Islands, Alaska 



Amchitka Islands, Aleutian Islands, Alaska 



Amchitka Islands, Aleutian Islands, Alaska (low water) 



Constantine Harbor, Aleutian Islands, Alaska 



...do 



Captains Harbor, Unalaska, Aleutian Islands, Alaska. .. 

 East side Simeonoff Island, Shumagin Islands, Alaska... 



Type. 



