Description of two New Species of Shelis. 101 
Art. XIV.—Description of two New Species of Shells ; by Wi- 
Liam Case, Cleveland, Ohio. 
Helix annulata— figs. 1, 2,3.) Shell minute, much depressed 
—umbilicus showing all the volutions ; aperture simple and some- 
Fig. 2. 
Fig. 1. 
what oval ; whorls four, banded by thin, sharp and parallel ribs, 
inclining slightly forward ; intercostal space marked with waved 
lines, running parallel with the whorls; nearly transparent ; 
diameter about one line. 
This minute but beautiful shell was found by Captain B. A. 
Stanard, in the region about Lake Superior, and I have heard of 
its being observed in other places, but so far as I can learn, it is 
undescribed. It differs from any description of the pulchella I 
have yet met with, in having uniformly an oval aperture 
simple lip. The H. minuta of Say, I believe never has the par- 
allel ribs, and is supplied with a lip. 
Planorbis multivolvis—(figs. 4, 5.) Shell about 
five-eighths of an inch in diameter ; whorls seven, | @ 
about half of the last whorl overlapping the prece- @& 
ding one, sometimes the last whorl suddenly dis- \& 
torted and expanded for the last half of its length ; 
ight side concave, left side slightly accuminate — Fig. 5. 
and considerably carinate; throat campanulate ; 
aperture opening towards the left, but projecting on ff 
both sides beyond the preceding whorl. 
This shell, also, I obtained from Captain Stanard, fo 
who found it in the northern part of Michigan. It ca 
is very distinct from any Planorbis I have met with, or have been 
able to find any description of. I have named it from its strong 
characteristic—a greater number of whorls than usual in the 
genus, natin 
Fig. 4. 
Note.—The Helix here described approaches the pulchella, 
(minuta of Say,) a ribbed variety of which is called H. costata ; 
yet it appears to be a distinct species. The Planorbis is most 
nearly allied to the P. campanulatus.— G. 
