250 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



three by a triple row, the median one of which is very slender on all 

 but the last turn and is situated a little nearer the posterior row than 

 the suprasutural one. There are twenty tubercles upon the second 

 and twenty-six upon the penultimate turn. These tubercles are 

 joined by moderately strong spiral bands and axial riblets which 

 inclose strongly impressed rounded pits between them. The periph- 

 ery is marked by a keel almost as strong as the supraperipheral 

 one, while the base, which is uniformly dark brown, bears two 

 prominent keels, the anterior one of which is well upon the short, 

 stout columella. The channels between these keels are crossed by 

 the feeble extensions of the axial riblets. Aperture strongly chan- 

 neled anteriorly and posteriorly; columella and parietal wall covered 

 with a strong callus. 



The type and two additional specimens. Cat. No. 32216, U.S.N.M., 

 come from Monterey, California. The type has the last seven whorls 

 and measures: length, 4.6 mm.; diameter, 2.2 mm. Two other 

 specimens. Cat. No. 56015, IJ.S.N.M., come from the same locality, 

 and a sixth, in the collection of Mr. S. vS. Berry, was dredged in 12 

 fathoms off Del Monte, Monterey Bay, California. 



TRIPHORIS PEDROANUS, new species. 

 Plate XVI, fig. 1. 



Shell sinistral, elongate-conic, light brown. Nuclear whorls four, 

 increasing regularly in size. The first three smooth, probably by 

 erosion, the next faintly, obsoletely sculptured by about thirty-six 

 slender, equally strong and equally spaced, axial riblets and two slen- 

 der spiral threads, separated by a narrow chamiel near the periphery 

 of the whorl. Succeeding turns separated by broad and deep chan- 

 neled sutures; the first seven ornamented by two equally strong 

 spiral rows of tubercles, which are .separated by a chamiel, as wide as 

 that at the sutures. Beginning with the eighth turn, a slender tuber- 

 culate keel makes its appearance in this chamiel, situated a little 

 nearer the posterior keel than the suprasutural one. This keel 

 increases steadily in size and on the penultimate turn exceeds the 

 supraperipheral one in strength. On the last three turns the tubercles 

 of the posterior keel are a little more strongly developed than on the 

 other keels. On all the keels the tubercles slope a little more abruptly 

 at their posterior border, the anterior edge being gently rounded. 

 There are fifteen tubercles upon the first, seventeen upon the fifth, and 

 twenty-four upon the penultimate postnuclear turn. The tubercles 

 are connected spirally b}^ a moderately wide band and axially by 

 slender riblets, the spaces inclosed between these connections appear- 

 ing as rounded pits. The entire surface of the spire is crossed by 

 numerous microscopic spiral lines and lines of growth. Periphery of 



