FROM THE TERTIARY OF VIRGINIA. 201 
Length .21. Breadth .10 of an inch. 
Remarks.—Although this shell has no very peculiar characters, yet I cannot refer it 
to any described species. One or two species, the B. St. Hillairii and Dekayi, from 
Claiborne, are somewhat allied to it, but they are not identical. 
FAMILY MELANID/. 
GENUS PASITHEA, (Lea.) 
P. ExaRATA, Pu. 35. Fic. 44. 
P. testd subulatd, acuminata, crassa, imperforatd, nitente, costatd; spird valde attenuatd, mamillatd, ad apicem levi: 
suturis profundis, excavatis; anfractibus quindecim, planulatis, costis oblique longitudinalibus crebris planis; an- 
Fractu ultimo angulato; basi levi, politd; apertura parva, sub-quadratd, sub-effusd. 
Shell subulate, acuminate, thick, imperforate, shining, costate; spire very attenuate, mamillate, smooth at the 
apex, sutures deep, excavated; whorls fifteen, flattened, with numerous flat obliquely longitudinal ribs; last whorl 
angulate; base smooth, polished; mouth small, sub-quadrate, somewhat effuse. 
Length .35. Breadth .07 of an inch. 
Remarks.—The ribs are slightly oblique. They disappear at both sutures, which are 
triangular, smooth and deep. ‘They extend, on the last whorl no farther than the angle, 
leaving the base perfectly smooth. The mouth is ovately quadrate, with sharp angles 
where the columella and outer lip join the preceding whorls. 
This shell appears to resemble the Turritella laqueata, Con., but its larger size, mami- 
late apex, and angular mouth serve to distinguish it from that species. 
P. susuna, Pu. 35. Fie. 45. 
P. testi subulatd, crassd, imperforata, costatd, striatd; spird attenuatd, obtusd, mamillatd, ad apicem politd; suturis 
profundis; anfractibus octo, convexis; costis longitudinalibus magnis, crebris, prope basim obsoletis, planulatis, le- 
vibus; striis transversis, parvis, crebris, interruptis; ultimo anfractu rotundato; basi levi; apertura arctatd, ellipticd, 
subeffusd. 
Shell subulate, thick, imperforate, costate, striate; spire attenuate, obtuse, mamillate, polished at the apex; sutures 
deep; whorls eight, convex; coste longitudinal, large, numerous, obsolete near the base, flattened, smooth; striw trans- 
verse, small, numerous, interrupted ; last whorl rounded; base smooth; mouth narrow, elliptical, sub-effuse. 
Length .18, Breadth .05 of an inch. 
Remarks.—The cost continue almost to the base, when they disappear suddenly, 
leaving a small place smooth immediately behind the columella. The first whorl of the 
spire is round, somewhat twisted, smooth and polished, forming a remarkable mamelon. 
The transverse stria are very small and do not cross the coste. The mouth is slightly 
angular above, and somewhat effuse at base. 
This shell attains a greater size than that given above. I have several fragments of 
much larger specimens. 
P. rpurnea, Px. 35. Fic. 46. 
» j A * SA , ? eas a e — ee : 
P. testa subulatd, elongatd, tenut, politd, sub-perforatd, costatd, striata; spird attenuata, mamillatd, conica; suturis 
linearibus, impressis; anfractibus duodecim, sub-convexis; costis longitudinalibus, magnis, planis, levibus; prope 
suluram superiorem striis transversalibus parvis, crebris; prope suturam inferiorem striis transversalibus magnis, 
raris; anfractu ultimo rotundato; basi striald; perforatione pene obsoletd; apertura ovata. 
