( 34 ) (Cricostomata.) 
7. Cycrostoma. (1) Lam. 
Oval - spiral, mouth Mouth bordered by a | Yerrestrialand aqua- 
round or nearly round, callous pad. lic. 
closed entirely by a round, V. Animal, p. 66. 
thin, calcareous opercu- 
lum : peristoma complete. 
PI. 9, fig. 13, 14. 
8. Varyata. Muller. 
Rolled almost in the Fresh waters. ; 
same plane. PI. 9, fig. 22. Y. Animal, p. 66. 
9. Patupina. (2) Lam. 
Vivieara. Montfort. 
Oval-spiral; opercu- Mouth with a small Marine, and in stag- 
lum with an angle like angle towards the upper nant waters. 
that of the mouth. P1.9, part. VY. Animal, p. 66. 
fig. 45. 
40. Moxoponta. Lam. 
Oval, or conical ; oper- A blunt and slightly Marine. 
culum round, horny. Pl. projecting tooth at the —V. Animal, p. 66. 
9, fig. 25: base of the columella. 
Base flat or concaye. 
(1) Young Cyclostome may sometimes be confounded with the shell of the genus 
Turbo; for the upper part of the peristoma is not completed, that is to say, the 
lips do not join, before the adult state ; in the Turbo they always remain separated. 
The Missenau chain of hills near Mayence is composed of fossil Cyclostomex, not of 
Bulimi, and of two species which, according to M. de Ferussac, are again found in 
Quercy, Agenois, and in Silesia. M. Brongniart expects that the Cyclostome will 
hereafter be divided into two genera; the one aquatic, the other terrestrial. The 
C. mumia, Lam. pl. 4, fig. 1, belongs to the latter; it has only been found as yet 
in the 1st ox Lower Fresh Water Formation in the environs of Paris ; M. Brongniart 
conceives that on further investigation it may. be found to characterise it: the 
enlargement or projection of the upper part of the peristoma is uot unfrequent in 
the living species. All those indicated at Grignon differ from true Cyclostome, 
The Cyclostoma carinata of the canals of Egypt, Pl. 13, fig. 9; C. bulimoides of the 
environs of Alexandria, Pl. 8, fig. 13; C. unicolor, Pl. 8, fig. 15; and the Helix cre- 
nelata, Pl. 12, fig. 10; brought by Olivier, differ in form from all the other fresh- 
water shells yet known, and, as M. Brongniart justly observes, if found in the fossil 
tate, would certainly have been considered as-marme. 
(2) Foss. in Gravel and Alluvial Clay; London Clay ; Crag Marl. 
