352 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



CERITHIOPSIS EXCELSA Dall. 



Plate 36, fig. 1. 



Cerithiopsis excelsus Dall, Prof. Paper No. 59, U. S. Geol. Surv., 1909, p. 75. 



Shell very large, elongate-conic. (Nuclear whorls decollated.) 

 Post-nuclear whorls appressed at the summit, well rounded, marked by 

 poorly developed, rounded, almost vertical, axial ribs, of which 12 

 occur upon the first three of the remaining whorls, 14 upon the fourth 

 to sixth, 16 upon the seventh, 20 upon the eighth, 24 upon the ninth, 

 and 32 upon the penultimate turn. In addition to these axial ribs, 

 the shell is provided at irregular intervals with long varices. The 

 spiral sculpture consists of slender cords. These are of several 

 strengths. On the eighth whorl there are four equally strong, 

 which divide the space between the sutures into four subequal parts. 

 The first of these cords is at the summit. In addition to these four 

 there are four more spiral cords, less strong than those just men- 

 tioned, occupying the space midway between the other cords. On 

 the penultimate whorl additional slender threads, which are still 

 weaker, occur between the spirals just mentioned. The junctions of 

 the axial ribs and the spiral cords, particularly the stronger, form 

 feeble, rounded nodules. Suture strongly constricted. Periphery 

 of the last whorl marked by a spiral cord as strong as the strongest 

 between the sutures. Base well rounded, marked by six equal and 

 equally spaced spiral cords, in the spaces between which a slender 

 spiral thread is present. The aperture is obstructed by the matrix 

 and is strongly channeled anteriorly; outer lip slightly expanded and 

 thickened ; columella short and stout. 



The type (Cat. No. 107400, U.S.N.M.) comes from the Oregonian 

 Eocene of North Fork of Umpqua River, at Schrum's Ranch, station 

 2798. It measures: Length 20.5 mm., diameter 6.5 mm. 



CERITHIOPSIS CURTATA, new species. 

 Plate 36, fig. 3. 



Shell small, elongate-ovate, light brown. Nuclear whorls decol- 

 lated. Post-nuclear whorls moderately rounded, ornamented with 

 three spiral keels, of which the first is at the summit, the next imme- 

 diately adjacent to it, being separated from it by a strong, incised line 

 only, on all but the last whorl; on this it is a little more distant. The 

 third keel is immediately above the suture. In addition to the 

 spiral keels, the whorls are marked by slightly retractive, axial ribs 

 which are almost equal to the spiral keels in strength. Of these ribs, 

 14 occur upon the second, 16 upon the third, 18 upon the fourth, 20 

 upon the fifth and the penultimate whorl. The junctions of the axial 

 ribs and spiral keels form prominent tubercles which are truncated 

 posteriorly and slope gently anteriorly, while the spaces inclosed 



