252 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



columella. Aperture irregular, the main portion subcircular, strongly 

 channelled posteriorly and anteriorly; outer lip moderately strong, 

 columella short, stout, and decidedly twisted, covered partly by the 

 very strong purplish parietal callus. 



The type. Cat. No. 195377, U.S.N.M., comes from San Pedro, 

 California, and measures: Length, 5.2 mm.; diameter, 2.2 mm. 



This species differs from all the other Calif ornian Triphoris in hav- 

 ing the middle keel between the sutures best developed, forming a 

 prominent shoulder at this point, while the one at the summit is only 

 feebly represented, the reverse being true in the other species. 



TRIPHORIS CARPENTERI, new species. 



Plate XVI, lig. !(!. 



Triforis adversa Carpenter, Rept. Brit. Ass. Adv. Sci., 1863, p. 628, in part; not 

 Triphoris adversus- Montagu . 



Shell elongate-conic, almost cylindric, bleached, white. (Early 

 whorls decollated.) Later turns ornamented by three spiral ridges, of 

 which the posterior one is a little more strongly developed than the 

 other two and forms the summit of the whorls. The other two 

 spiral ridges are equal and equally spaced. In addition to the spiral 

 ridges, the whorls are marked by axial ribs, about as strong as the 

 spiral ridges, the intersection of the ribs and ridges forming strong 

 tubercles, while the spaces inclosed between them appear as deeply 

 impressed square pits. There appear to be about twenty-two tuber- 

 cles upon all the whorls. The sutures appear as broad, deep channels, 

 which are crossed by the extensions of the axial ribs. On the last 

 three turns the posterior edge of the peripheral keel is apparent in 

 the suture. In addition to the above sculpture, the entire surface of 

 the spire is marked with microscopic lines of growth and equally fine 

 spiral striations. Periphery of the last turn marked by a strong 

 spiral keel. Base marked by two strong rounded keels, of which the 

 posterior one is separated about as far from the peripheral keel as 

 that is separated from the supraperipheral one. The anterior keel of 

 the base is situated on the columella and is separated by a little wider 

 and deeper channel from the posterior keel tlian that is from its 

 posterior neighbor; anteriorly it is limited by a feebly impressed 

 groove. The channels of the base are crossed by weak continuations 

 of the axial riblets. Aperture ovate, strongly channelled anteriorly 

 and moderately so posteriorly; columella short, stout, and twisted; 

 covered by a strong callus which also extends over the parietal wall. 



The type. Cat. No. 15583, U.S.N.M., was collected in Neah Bay, 

 Washington, by J. G. Swan. It consists of the last eight turns, which 

 measure: Length, 7.2 mm.; diameter, 2.2 mm! 



