FAMILY 2. PERISTOMATA. ] 
ht 
“NI 
Valvata obtusa, Turton. 
Turbo thermalis (var.), Dillwyn. 
Helix fascicularis, Alten. 
Pl. CXCVI. Fig. 2. 
VALVATA CARINATA, Sowerby, Genera of Shells, No. 41. 
Valvata tricarinata (var.), Deshayes. 
PALUDINA, Lamarck. 
Testa ovata, vel conoidea, epidermide olivacea induta; spira subturrita, 
sepeé erosa, anfractibus rotundis, planiusculis, aut carinatis ; apertura 
rotunda, vel ovata, margine continuo, labro simplici, acuto. Oper- 
culum corneum, orbiculare, aut spirale, aut concentricum. 
We are again indebted to Geoffroy, who, like Draparnaud and Turton, 
devoted his attention more particularly to the land and freshwater mol- 
lusks, for an especial notice of the Paludine. He distinguished the com- 
mon typical example of this series by the name of the Vivipare-a-bandes, 
significant of its natural method of propagation ; Linnzus referred it to 
the Helices, and Draparnaud to the Cyclostomata; but when Cuvier, in 
his memoir on the anatomy of the Paludine, demonstrated the necessity 
of separating them on account of their being aquatic, they were set apart 
by Lamarck under the new title of Vivipara, a name which he afterwards 
changed for the one now commonly adopted. 
We have followed Lamarck in associating the Paludine in the same 
family with the Ampullarie, but they are not so closely allied to those 
mollusks as some authors have imagined ; Sowerby, nevertheless, at one 
time proposed to distinguish these two genera only by the difference of 
their opercula, by which arrangement all the horny operculated Ampulla- 
rie would be referred to the present genus. The proposition was, how- 
ever, made before the true nature and habits of the Ampullaric were 
known, and at a time when this author was somewhat enthusiastic in his 
