22 
obtusely fusiform ; suture distinct ; whorls six, obsoletely wrin- 
kled ; aperture longitudinally subovate ; exterior lip reflected, but 
not flattened, interrupted above by the penultimate whorl, and 
with five teeth, of which the superior one, and that which precedes 
the basal one, are smallest ; labrum with an undulated lamelliform 
tooth, its anterior extremity little elevated, but elongated so as 
almost to join the superior extremity of the exterior lip. 
Length three-twentieths of an inch. Inhabits Upper Missouri. 
Var. a. — The two smaller teeth obsolete or wanting. Yar. b. — 
The basal tooth obsolete or wanting. 
Very distinct from corticaria^ it being a much larger and pro- 
portionally more dilated shell ; and with that species and the next 
seems to belong more properly to the genus carychium of Muller 
and Ferussac. 
P. RUPiooLA. — Shell dextral, attenuated to an obtuse apex, 
white ; whorls six, glabrous ; suture deeply impressed ; labrum 
bidentate ; superior tooth lamelliform, emarginate in the middle, and 
at the anterior tip obtusely uniting with the superior termination of 
the labium ; inferior tooth placed upon the columella, and extend- 
ing nearly at a right angle with the preceding ; labrum, tridentate, 
teeth placed somewhat alternately with those of the labium, infe- 
rior tooth situated at the base and immediately beneath the inferior 
tooth of the labium. 
Lenofth about one-tenth of an inch. Inhabits East Florida. 
I formerly found it abundant on the banks of St. John Kiver, 
in East Florida, and more particularly under the ruins of Fort 
Picolata, under stones, &c. 
It is about the size of P. corticaria^ and considerably resembles 
that species, but it is sufficiently distinguished by the circumstance 
of its gradually decreasing in diameter from the body whorl, to its 
obtuse tip ; and, in the character of the mouth, it is widely dis- 
tinct. 
SucciNEA ovALis. — (Jour. Acad. Nat. Sc. vol. i. p. 15.) A 
large variety of this species is found very common on the Missouri, 
of the length of about four-fifths of an inch ; I observed one speci- 
men which was upwards of an inch long. 
Cyclostoma marginata. — Shell turreted, pale horn color, or 
dusky, obsoletely wrinkled across ; suture rather deeply impressed ; 
volutions six ; aperture mutic, suboval, truncated transversely 
