22 
obtusely fusiform ; suture distinct ; uhorls 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 IMissouri. 
Var. a. — The two smaller teeth obsolete or wanting. Var. b. — 
The basal tooth obsolete or wanting. 
Very distinct from corticaria, it being a much larger and pro- 
portionally more dilated shell ; and w'ith that species and the next 
seems to belong more properly to the genus carychium of Muller 
and Ferussac. 
P. RUPICOLA. — Shell dextral, attenuated to an obtuse apex, 
white ; whorls six, glabrous ; suture deeply impressed ; labrum 
bidentate ; superior tooth lamiform, 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. 
Length about one-tenth of an inch. Inhabits East Florida. 
I formerly found it abundant on the banks of St. John River, 
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 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 obserA-ed one speci- 
men which was upwards of an inch long. 
Cyclostoma margin.ata. — Shell turreted, pale horn color, or 
dusky, obsoletely wrinkled across ; suture rather deeply impressed ; 
volutions six ; aperture mutic, suboval, truncated transversely 
