12 BOOK OF SPECIES. 
sions elongated, arcuated and transverse, situ- 
ated under the posterior margin. 
P. uneaRIcA. Conical, finely striated lon- 
gitudinally, and somewhat wrinkled transversely ; 
summit recurved and spiral; base roundish, from 
one inch to two in diameter, often coated with a 
brown shaggy epidermis ; inside white or pinkish. 
B. large. W. 37. 41. 
P. mirruLA. Roundish ovate, obliquely coni- 
cal, solid, whitish, with concentric imbricated 
wrinkles ; summit slightly recurved; small. B. 
W. 37. 43. 
P. intorTA. Ovate-roundish, peculiarly ob- 
liquely conical, white, with obsolete longitudinal 
strie ; summit lateral, exserted, and spirally 
twisted ;- small. 
CALYPTREA. 
Conical; base orbicular, and summit vertical, wm- 
perforate, and acute; internal cavity with a 
spiral septum. 
C. exTINcrorRiuMm. Sub-orbicular, conical, 
whitish, and rather smooth, with unequal spiral 
circles; summit sub-acute. 1. WS. 8. 5. 
C. Ltevieata. Orbicular-depressed, nearly 
