Greenes new sjoecies of Achatina. 
47 
mens the indication of a second ridge near the anterior end; 
both these ridges are alternately raised and depressed— 
periostracha much wrinkled by the striae, of a light horn 
colour, and remarkably glabrous — in old and young speci- 
mens it is darker than in the perfect shell — and the young 
are often beautifully rayed and spotted with brown — nacre 
commonly white, pearly, and undescent — teeth moderately 
thick — length about two inches — breadth about four. 
This shell inhabits probably all our western waters; and 
it is a little remarkable that Prof. Rafinesque, who has de- 
scribed and figured so many of the TJNioNiDiE, should have 
omitted this remarkable species. I found eight or ten of 
these shells in the rivers in the neighbourhood of Pitts^- 
burg. In old shells the anterior margin is often produced 
and truncated — and the young specimens seem to be pecu- 
liarly liable to a preternatural enlargement of some portions 
of the shell, more than others. 
Description of two neio species of Achatina, from the 
Sandwich Islands — ivith some remarks on the Ti, the 
plant on which these shells are commonly found. Br 
J. Green, A. M. Prof, of Chem. in Jeff. Med. College, 
Read May 14, 1827. 
.ACHATINA Stewartii. 
testa sinistrorsa — ovato — oblonga — lutescente, minu- 
tissime striata — colore varia, nunc unicolore, nunc 
diver sissime facial a — collumella rosea — lahro tenui — ■ 
intus alhido. — Plate 4, figs. 1,2^ 3, 4. 
Stewart's Achatina. — Shell heterostophe — conical — • 
oblong — about one inch in length and half an inch in diam- 
eter — whorls six or seven, rounded and marked with nu- 
merous oblique and delicate striae — apex rather obtuse and 
