MOLLUSCS. 
2S7 
liber naturliclie Gruppirung und geograpliisclie Verbreitung der 
gedeckelten Land-Schnecken/^ [Remarks on the natural ar- 
rangement and geographical distribution of the operculated 
Land-snails.] Pfeiff. Malacol. Rlatt. 1864, pp. 131-144 : 
The Cydostomacea form, with regard to their facies and their geographical 
distribution, two divisions : tliose mth a round operculum of many whorls, 
most abundant in Eastern Asia and the adjoining archipelagos, some occur- 
ring also in Tropical America, but entirely absent on the continent of Africa 
and in Europe ; and those with ovate operculum of few whorls, inhabiting 
Eastern Africa and the adjoining islands, Europe, Western Asia, and lihewise 
very abundant in the West Indies, but represented by a few aberrant forms 
only {Realia and Omphalotropis) in Eastern Asia *, Australia, and the islands 
of the Pacific. ' 
Ildicina, like the first division, inhabits Eastern Asia and Tropical America ; 
but these two regions are in some measure connected by the frequent occur- 
rence of this genus in the Pacific islands. The operculated land-snails found 
beyond the tropics are few in number, and belong to very different genera in 
the diflerent regions : Cydostoma, Pomatias, and Acicula in Europe ; CydotuSj 
Cydophorus [and Hdicina] in Asia; Ildicina in America. From Western* 
Africa, the continent of Australia south of the tropics, and from the same 
portion of America no operculated land-snail is known up to the present timef. 
The genus Otopoma might better be cancelled and ite species distributed 
between Cydostoma, Cydotus, and others. Ilyclrocena is quite distinct from 
Omphalotropis ; but the latter is scarcely worthy of distinction from Realia. 
Many of the species enumerated as Omphalotropis are Assiminecc. 
Cyclostomacea. 
New genera proposed by Blanford, Ann. & Mag. Nat. Hist, 
1864, xiii. ; — 
Cydotojisis, g. n., p. 447 ; type Cydotus semistriatus (Sowerby, Pfr.). We 
cannot agree with the author, who places it in the Cydostomidcc proper, that is, 
the Cydostomacea with an operculum of few whorls. 
Lagochcilus (Theobald, MS.), p. 462, a new subgenus for Oyclophorus scissi- 
margo (Bens.). 
Craspedotropis, p. 454, subgeneric name for some species of Cydophorus, as 
C. involvulus (Muller) and others. 
Lcptopoma is regarded as a subgenus of Cydophorus. 
Opistlioporus is subordinated to Spiracultmi as a subgenus. 
Cyathopoma, g. n., p. 449 ; type Cyclotus Jilocinctus (Bens.). 
Jerdonia, g. n., proposed in Journ. As. Soc. Beng. 1801, is now fully cha- 
racterized, p. 448 ; type J. trochlea. 
Cyclotus. The species arranged in natural groups by the Recorder in 
* A true Otopoma and a Pomatias lately discovered by Mr. Theobald in 
Trans^angetic India, would appear to form exceptions to the general rule 
established in our paper, but they cannot overthrow it, the contrast between 
Western and Eastern Asia remaining very striking. 
t Mr. Cox mentions two species of Cydophorus from S. W. Australia. 
