NO. 2055. MARINE M0LLU8K8— HENDERSON AND BARTSCH. 419 



ovate; posterior angle acute; outer lip thin; inner lip slightly curved 

 and somewhat revolute, provided with a strong, oblique fold at its 

 posterior extremity; parietal wall glazed with a thin callus. 



The type, Cat. No. 252577, U.S.N.M., has 7 post-nuclear whorls 

 and measures: Length, 2.4 mm.; diameter, 1 mm., and it was 

 dredged at Chincoteague Bay, Virginia. 



TRIPHORIS PYRRHA, new species. 

 Plate 14, fig. 1. 



Shell broadly conic, white. Nuclear whorls 4, the first half of the 

 first turn smooth, the rest marked by 2 spiral cords and numerous 

 very fine axial threads. Post-nuclear whorls well rounded, the first 

 4 marked with 2 tuberculated spiral cords, of which one is immedi- 

 ately below the summit and the other a little posterior to the pe- 

 riphery. Beginning with the fifth whorl a third spiral thread makes 

 its appearance between the two, and on the last turn attains a size 

 equal to the one posterior to the periphery. In addition to the spiral 

 cords, weak axial riblets are present, which render the spiral cords 

 tuberculated, 16 tubercles appearing on the first and second whorl, 

 18 upon the third and fourth, 20 upon the remaining. Suture some- 

 what channeled. Periphery of the last whorl marked by a strong 

 spiral cord, which is separated from the supraperipheral spiral cord 

 by a sulcus as wide as that which separates the supraperipheral cord 

 from the median. This sulcus is crossed by the continuations of the 

 axial riblets, which stop at its posterior margin. Base moderately 

 produced, marked by two spiral cords, one at the insertion of the 

 columella and the other halfway between this and the peripheral 

 cord. Aperture irregular, decidedly channeled anteriorly (outer lip 

 fractured, thin) ; inner lip appressed to the base, and fused with the 

 heavy callus which covers the parietal wall and renders the peritreme 

 complete. 



The type, Cat. No. 252571, U.S.N.M., was dredged at Chinco- 

 teague. It has 7 post-nuclear whorls, and measures: Length, 2.7 

 mm.; diameter, 0.9 mm. 



TRIPHORIS NIGROCmCTA C. B. Adams. 



DIASTOMA VIRGINICA, new species. 

 Plate 14, fig. 3. 



Shell elongate-conic. The early whorls are chestnut brown, the 

 succeeding turns flesh colored, mottled and variegated with brown; 

 m some specimens the chestnut brown extends over the entire shell. 

 Nuclear whorls two and one-half, well rounded, smooth. The first 

 3 post-nuclear whorls rather well rounded ; the succeeding turns less 

 so, while the later ones are almost flat. The whorls are marked with 



