260 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxxiii. 



of the columella, is smooth and separated a little more distantly 

 from its neighbor. The supraperipheral and basal channels are 

 crossed by the continuation of the axial ribs. Aperture (?) frac- 

 tured; columella stout and twisted, covered by a strong callus which 

 extends over the parietal wall. 



The type, Cat. No. 207, C. B. Adams collection, Amherst College, 

 Amherst, Massachusetts, has fifteen whorls, and measures: Length, 

 4.8 mm.; diameter, 1.5 mm. 



There are two other specimens in the type lot, all of which were 

 collected by Dr. ('. B. Adams at Panama. 



TRIPHORIS GALAPAGENSIS, new species. 

 Plate XVI, fig. 7. 



Shell small, acicular, with the keel at the summit and the base 

 light brown, the rest white. Nuclear whorls five, ornamented with 

 two ratlier closely placed spiral threads, the posterior one of which 

 marks the middle of the exposed portions of the nuclear whorls, and 

 many slender, axial riblets, of which there are about twenty-four 

 upon the fourth and twenty-eight upon the fifth turn. Post-nuclear 

 whorls eight, separated by deep channeled sutures, ornamented on 

 the early whorls by two strongly tuberculated keels, separated by a 

 deep channel, which is crossed by the moderately strong axial rib- 

 lets, which connect the tubercles of the two ridges. Beginning with 

 the fourth whorl a slender keel makes its appearance between the 

 other two, which rapidly increases in size, becomes tuberculated, 

 and on the penultimate and last turn exceeds the basal keel in 

 strength. There are about fourteen riblets U])on the first, twenty 

 upon the fifth, and twenty-two upon the penultimate, post-nuclear 

 whorl. Base marked by three non-tul:)erculated, equally strong and 

 equally spaced sj^iral ridges. Aperture irregular, pyriform, strongly 

 channeled posteriorly and anteriorly, with a rounded opening at the 

 anterior extremity of the short, stout, twisted columella. Parietal 

 wall and columella covered by a strong callus. 



The type and six specimens. Cat. No. 195380, U.S.N.M., were 

 dredged by the steamer Alhatross of the United States Bureau of 

 Fisheries, at Station 2813, in 40 fathoms, off the Galapagos Islands. 

 The type has thirteen whorls, and m.easures: Length, 3.2 mm.; 

 diameter, 1.1 mm. 



Two striking color forms of this species were found in the lot 

 obtained from the above station. One, represented by a single 

 specimen, Cat. No. 105380, U.S.N.M., which may be known as 

 variety postalhus, fig. 5, has the posterior and median keel white, 

 the rest brown. The other variety, unicolor, fig. 13, represented by 

 nine specimens, Cat. No. 105379, U.S.N.M., is uniformly brown. 



