358 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



marked by two spiral cords of which the first is immediately below 

 the peripheral sulcus, while the next, which is less strong, is sepa- 

 rated from it by a narrow channel. The anterior limit of this cord 

 is a mere impressed line. There is another impressed line a little 

 anterior to this one. Aperture decidedly channeled anteriorly; 

 posterior angle obtuse (outer lip fractured); columella short, stout, 

 curved, and slightly twisted. 



The type (Cat. No. 195195, U.S.N.M.) has nine and a half post- 

 nuclear whorls remaining and measures: Length 5.4 mm., diameter 

 1.8 mm. It comes from San Pedro Bay, California 



Named for Dr. Ralph Arnold. 



CERITHIOPSIS MAGELLANICA, new species. 



Plate 38, fig. 8. 



Shell broadly elongate-conic, light brown. (Nuclear whorls 

 decollated.) Post-nuclear whorls appressed at the summit, not 

 shouldered, well rounded, ornamented with three low, broad, 

 spiral keels, which are at least twice as wide as the spaces that 

 separate them. The first of these keels is a little below the summit, 

 the second is median, and the third a little anterior to the suture. 

 The middle keel is about one and one-fourth times as wide as the 

 other two, which are equal. In addition to this spiral sculpture, 

 the whorls are marked by decidedly curved, somewhat retractive, 

 low, rounded, axial ribs. Of these, 20 occur upon the second of 

 the remaining turns, 24 upon the third, 26 upon the fourth and fifth, 

 28 upon the sixth, and 30 upon the penultimate turn. The junc- 

 tions of the axial ribs and spiral cords form low, elongated tubercles, 

 which have their long axes parallel with the axial sculpture. The 

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

 rounded pits. Sutures moderately constricted, showing the basal 

 cord. Periphery of the last whorl marked by a slender groove as 

 wide as those separating the first supraperipheral cord from the 

 median and, like them, crossed by the feeble continuations of the 

 axial ribs. Base of the last whorl well rounded, marked by at least 

 two low, very feeble, broad, spiral cords on the posterior half; the 

 anterior half apparently smooth. Aperture quite large, decidedly 

 channeled anteriorly; posterior angle obtuse; outer lip rendered 

 sinuous by the external sculpture; columella very curved and reflected; 

 parietal wall glazed with a thin callus. 



The type has the last eight post-nuclear whorls and measures: 

 Length 8.5 mm., diameter 2.5 mm. It and another specimen (Cat. 

 No. 96224, U.S.N.M.) come from the U. S. Bureau of Fisheries 

 station 2778, in 61 fathoms, sand bottom, bottom temperature 48°, 

 from the Straits of Magellan. 



