( 30 ) _ (Ellipsostomata.) 
14. Oposromra. Fleming. 
Spire produced; mouth With teeth or plates. The greater number 
contracted , subangular , terrestrial; under stones, 
distinct ‘from the body on rocks, and in mosses. 
whorl. Animal unknown. 
a, Spire dextral. Pl. 8, fig. 28. 
bos. sinistral, Pl. 8) fig 523. 
15. Pura. (1) Lam. 
Summit obtuse; mouth = Withor without teeth Marine and Terres- 
narrowed byacallous pad, or plates. trial. 
and qunihitied on the side V. Animal, p. 62. 
of the spire by the prece- 
ding whorl. Pl. 6, fig. 37, 
34. 
a Without a tooth, pl. 8, fig. 29. 
6 A tooth in the part of the mouth invaded by the penulti- 
timate whorl, pl. 8, fig. 32. - 
e Teeth within the outer lip, pl. 6, fig. 37. 
Oval { d Chondrus, Cuv. Teeth at the lip, or plates within the mouth, 
: pl. 8, fig. 24. 
Cylindrical. 
C. Horizontally volute ; mouth transyersally elliptical. 
16. Pranoruis. (2) Brug. 
Rolled almost in the Slagnant waters. 
same plan ; the whorls in- V. Animal, p. 63. 
creasing gradually ; no 
operculum. Pl. 6, fig. 32. 
47. Hex. (8) 
Globulous or subconical, Pappesteant 
spire depressed ; mouth V. Animal, p. 62. 
somewhat diminished by 
the projection of the pen- 
ultimate whorl. Pl. 7. 
(1) The shells of the marine and terrestrial Pup are similar, but an experienced 
Conchologist may always distinguish them : the animal of the former is not known. 
Lamarck doubts the Pupa mumia to be marine. Foss. in the 2d Fresh Water 
Formation. 
(2) Fossil species have been found in the Limestone of Fontainebleau (2d Fresh 
Water Formation) ; in the Silea near Paliseau (2nd Fresh Water Formation) ; in the 
Marne Blanche covering the Gypsum at Pantin and Chaumont (1st Fresh Water For- 
mation); in the Cowes Rock of Limestone ; London Clay ; Green Sand ; Under Oolite ; 
Derbyshire Peak Limestone. Neither of the three Planorbes cited at Grignon can be 
exactly referred to this Genus ; the Carinata resembles the Delphinata. 
(3) ‘The distinction of fresh water formations, so precisely established by Geo- 
logists, has made it indispensably necessary to study this Genus attentively. An ar- 
rangement with a view of easily distinguishing the species is difficult, from the 
great accumulation, for whilst the shells present the greatest varieties of form, the 
animals offer no differences of any importance. As M. de Ferussac appears to 
have studied the excessively numerous species of tl:is Genus more completely than 
any other author, accompanying the BE Ft of his system, which comprebends 
all the known species, with accurate and beautiful engravings, J shall adjoin bis 
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