252 NEW FOSSIL SHELLS 



Shell subulate, elongated, thin, polished, sub-perforate, costate, striate; spire attenuate, mamillate, conical; sutures 

 linear, impressed; whorls twelve, slightly convex; ribs longitudinal, large, flat, smooth; strice transverse, near the 

 upper suture small and numerous, near the lower suture large and unfrequent; last whorl rounded; base striate; per- 

 foration almost obsolete; mouth ovate. 



Length .41. Breadth .10 of an inch. 



Remarks. The transverse striae do not cross the ribs, which are perfectly smooth and 

 polished. The whorls are divided about the middle by a deep impressed line. Above 

 it is a series of close, small striae; below it the striae are larger and more distant. On the 

 body whorl they end at a rather deeper line about the middle. Here also the ribs end, 

 and there is a smooth space before the striae of the base commence. These are rather 

 large and not numerous. The mouth is acutely angular above and rounded below. 

 The outer lip is sharp. 



This elegant little shell is remarkable for its ivory-like appearance. The peculiar 

 arrangement of its transverse striae distinguishes it from all other species. 



P. L^VIGATA, PL. 35. FIG. 47. 



P- testa elevato-conicd, acuminatdj imperforatd, crassd, leevi, eburned, nitente; spird attenuatd, conicd, acutd; su- 



turis linearibuSj minimis; anfractibus , plants; anfractu ultimo sub-angulato; basilcevi; aperturd oblique quad- 



rilaterali. superne et inferne acute angulatd, effusd. 



Shell elevated-conical, acuminate, imperforate, thick, smooth, ivory-like, shining; spire attenuate, conical, acute; 

 sutures linear, very small, whorls 'flat; last whorl somewhat angular; base smooth; aperture obliquely quadri- 

 lateral, acutely angular above and below; effuse. 



Length .08. Breadth .10 of an inch. 



Remarks. The whorls are perfectly flat, so that the outlines of the spire are straight. 

 The surface of the shell is remarkably smooth and shining. 



In my largest specimen the lower whorls have been broken off, so that I am unable to 

 give their number. This fragment, however, has about eleven. 



This shell bears some resemblance to the P. aciculata, Lea, from Claiborne, but it 

 may readily be distinguished by its larger size, less attenuate shape, and flatter whorls. 



P. OVULUM, PL. 35. FIG. 48. 



P. testa ovaid, sub-elongatd, tenui, imperforatd, Icevi, nitente; spird breviusculd, ovatd, obtusd; suturis profundis, 

 llnearibus; anfractibus quatuor. convexis; anfractu ultimo rotundato; bast Itevi; aperturd ovatd; columelld crassd, latd; 

 Itevi. 



Shell ovate, somewhat elongate, thin, imperforate, smooth, shining; spire rather short, ovate, obtuse; sutures deep, 

 linear; whorls four, convex; last whorl rounded; base smooth; mouth ovate; columella thick, wide, smooth. 



Length .15. Breadth .08 of an inch. 



Remarks. The mouth is angular above and rounded below. The sutures are deep, 

 owing to a slight conical depression of the whorls immediately at their junction with 

 those above. 



I know no species to which the above is allied. 



P. DIAPHANA, PL. 35. FIG. 49. 



P. testa ovato-elongatd, acuminatd, tenui, sub-perforatd, diaphand, striata; spird subattenuatd, mamillatd; suturis 

 impressis, linear i bus; anfractibus sex, convexis; striis minutis, transversalibus ; anfractu ultimo rotundato; basi 

 striata; aperlurd elongato-quadratd, sub-effusd. 



