258 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



are separated by a channel a little deeper and wider than the channel 

 wliich separates the middle keel from the first. The third keel is the 

 least developed and is situated on the base of the columella. The 

 anterior part of the base, including the median keel, is of light-brown 

 color. Aperture irregular, the main portion circular. The posterior 

 slit closed at the edge, but with a circular perforation a little distance 

 behind the edge; anteriorly the outer lip is closely appressed to the 

 columella, but a circular perforation is present at the base of the 

 columella. Columella short and decidedly twisted. The type has 

 seventeen whorls, and measures: Length, 6.5 mm.; diameter, 2.0 mm. 

 The type and tlu-ee specimens, Cat. No. 195375, U.S.N.M., were 

 dredged by the steamer Albatross, of the U. S. Bm-eau of Fisheries, 

 at Station 2798, in 18 fathoms in the Bay of Panama. 



TRIPHORIS INCONSPICUUS C. B. Adams. 



Plate XVI, fig. 15. 



Triphoris inconspicuus C. B. Adams, Ann. Lye. Nat. Hist. N. Y., 1852, j^. 383. 



Shell small and slender, reddish brown fading to redcUsh yellow on 

 the last turn, with the supra-sutural keel yellowish white. Nuclear 

 whorls fine, the first two yellowish white, feebly sculptured, the other 

 three brown, marked by two strong narrow spiral tlireads, wliich 

 cUvide the space between the sutures into three parts, of which the 

 anterior two are about equal wliile the posterior one is a little wider 

 than the rest. In addition to the spiral threads, the surface is marked 

 by regular, slender, axial riblets, which are about as strong as the 

 spiral threads ; of these there are about twenty-four upon the fourth 

 and twenty-eight upon the fifth turn. Post-nuclear whorls sepa- 

 rated by deeply channeled sutures, ornamented on. the early whorls 

 by two narrow, tuberculate, spiral keels, which are separated by a 

 very wide channel. The tubercles are connected across tliis channel 

 by the rather strong, protractive, axial riblets, of which there are about 

 sixteen upon the first, twenty-two upon the fifth, and twenty-six upon 

 the penultimate post-nuclear whorls. Beginning with the fifth post- 

 nuclear turn, the middle band makes its appearance in the middle 

 of the channel. This increases steadily in size, but attains only about 

 half the size of the anterior keel on the last turn. In adchtion to this 

 strong sculpture, the entire surface of the spire, tubercles, and inter- 

 spaces are marked by microscopic lines of growth and spiral striations. 

 Periphery of the last whorl marked by a rather narrow deep channel. 

 Base with three prominent, equally strong, and equally spaced keels. 

 The peripheral sulcus and the two basal sulci between the keels are 

 marked by the continuations of the axial riblets. Aperture irregular, 

 pyriform, decidedly channeled posteriorily, main portion subcircular; 

 parietal wall covered with a very thick callus, wliich extends down 

 along the short, stout, and anteriorily decidedly twisted columella. 



