GASTEROPODA. 11 
Suewt rather larger, and of a firmer structure than most species, 
rather opaque, and of a dull surface. It is of a subcircular, depressed 
form, obtusely angular at the periphery, and composed of about three 
and a half rapidly increasing, convex whorls, separated by a deep 
suture, and having the apex nearly central. The colour is tawny 
yellow. The strie of increment are coarse, somewhat irregular, and 
the surface, except near the umbilicus, and more especially above, is 
wrinkled with sinuous, branching furrows, not conformmg to either 
axis of the shell, Aperture nearly circular, the penultimate whorl 
but slightly encroaching upon it; lip simple, the columellar portion 
reflected against a rather large umbilical perforation, and produced 
above in the form of a delicate white callus, which is seen to revolve 
within the shell in the direction of the spire. 
Largest diameter nearly half an inch ; axis one-fifth of an inch. 
Obtained by Mr. Couthouy on the island of Kauai, Sandwich 
Islands. 
A large and substantial species, easily distinguished by the branch- 
ing wrinkles of the surface, which probably correspond to the blood- 
vessels of the animal. 
Figure 9, front view of the shell; 9 a, view from above. 
VITRINA TENELLA (Gould). 
Testa parva, V. pellucide simillima, succinea, sub-perforata, gradibus 
etatis conspicuis striata: spira rotundata, apice subcentralt, anfracti- 
bus tribus, convexis, declivibus ; sutura excavata: apertura sub-circu- 
laris ; labro antrorsum arcuato. 
SHELL minute, fragile, pellucid, heliciform, rather globose, of a pale 
amber-colour, and with a slight umbilical depression. The spire is 
elevated and obtusely rounded, composed of three convex whorls, the 
outer one large and sloping, separated by a deeply impressed suture, 
and distinctly marked by the lines of growth. Aperture nearly cir- 
cular, rather large, the lip curving forwards, so as to be protruded at 
the middle. 
