NO, 2055. MARINE M0LLU8K8— HENDERSON AND BARTSCH. 415 



TURBONILLA (PYRGISCUS) POWHATANI, new species. 

 Plate 13, fig. 5. 



Shell broadly conic, yellowish white. Nuclear whorls decollated. 

 Post-nuclear whorls moderately well rounded, feebly shouldered 

 at the summit, marked by strong, almost vertical axial ribs, of which 

 22 occur upon the third, 24 upon the fourth, 26 upon the fifth and 

 seventh, and 28 upon the penultimate turn. These ribs are almost 

 as wide as the spaces that separate them. Intercostal spaces- crossed 

 by 7 equal and equally spaced, strongly incised spiral Hnes. Suture 

 strongly marked. Periphery of the last whorl well rounded. Base 

 short, well rounded, marked by the continuations of the axial ribs, 

 which extend to the umbihcal chink, and 5 or 6 feebly mcised, irregu- 

 larly spaced spiral lines. Aperture oval; posterior angle acute; outer 

 lip thin, showing the external sculpture within by transmitted light; 

 inner lip somewhat twisted, slightly revolute; parietal wall covered 

 with a moderately thick callus. 



The type, Cat. No. 252574, U.S.N.M., was dredged at Chincoteague, 

 Virginia. It has 7^ post-nuclear whorls, and measures: Length, 

 5 mm.; diameter, 1.8 mm. 



TURBONJLLA (PYRGISCUS) POCAHONTASAE, new species. 

 Plate 14, fig. 4. 



Shell broadly conic, bluish white. Nuclear whorls 2 J, forming 

 a depressed hehcoid spire, the axis of which is almost at right angles 

 to the axis of the succeeding turns, in the first of which it is partly 

 immersed. Post-nuclear whorls very slightly rounded, moderately 

 shouldered at the summit, marked by strong, slightly pro tractive, 

 broad, well rounded, somewhat curved axial ribs, of which 18 occur 

 upon all the whorls. The intercostal spaces are about twice as broad 

 as the axial ribs. They are well rounded and shallow. They are 

 marked by 5 broad spiral grooves and a number of fine incised lines. 

 The space between the summit and the first broad groove is about 

 twice as wide as that between any of the grooves. This space is 

 crossed by 6 fine incised spiral lines, which are not quite equally 

 spaced, the second and third and the fourth and fifth being a little 

 closer to each other than the others. The space between the first 

 broad groove and the second is crossed by a strongly incised fine 

 spiral line, and the space between the third and fourth is likewise 

 crossed by a fine incised line. Suture well impressed. Periphery 

 of the last whorl feebly angulated, marking the termination cf the 

 axial ribs. Base very short, well rounded, marked by 19 well-incised 

 fine spiral lines, which grow successively closer spaced from the 

 periphery to the umbilical area. Aperture subquadrate; posterior 

 angle obtuse; outer lip thin, showing the external sculpture within; 



