70 CLASS GASTEROPODA. 
either smooth or tuberculated. Species with a crowned spire : 
Con. cedonulli, L., &c. Species with a simple spire: Con. 
litteratus, L., &c. The appellation of crowned spire is ap- 
plied to that which is studded with tubercles. 
Cypreaa, L. 
The spire projecting but little, and the aperture narrowed, 
and extending from one extremity to the other; but the shell, 
which is: protuberant in the middle, and almost equally 
narrowed at both ends, forms an oval, and the aperture in the 
adult animal is transversely wrinkled on each side. The 
mantle is sufficiently ample to fold over and envelope the shell, 
which, at a certain age, it covers with a layer of another 
colour, so that this difference, added to the form acquired by 
the aperture, may easily cause the adult to be taken for ano- 
ther species. The animal has moderate tentacula, with the 
eyes at their external base, and a thin foot without an opercu- 
lum. 
The colours of these shells also are extremely beautiful : 
they are very common in cabinets, though with very few ex- 
ceptions they all inhabit the seas of tropical countries. They 
are termed Porcelainous. 
ANULA, Brug. 
The shell is oval, and the aperture narrowed and long, as in 
cyprxa, but without folds on the side next to the columella; 
the spireis concealed, and the two ends of the aperture equally 
emarginated, or equally prolonged in a canal. Linnzus con- 
founded them with the bulle, from which Bruguiéres has 
very properly separated them. The animal has a broad foot, 
an extended mantle which partly folds over the shell, a mode- 
rate and obtuse snout, and two long tentacula, on which, at 
about a third of their length, are the eyes. 
