OF SOUTHERN INDIA. 207 
By far the largest number of the Honostomata belonging to the above-named 
families, (with few exceptions, Narrcrps, probably Scaxip~, and others) are vegetable 
feeders ; their teeth are usually small and numerous, for which reason they are 
classed by Dr. Gray and others in the divisions Preno-and Tmn10-GLossara. 
The animals inhabit the sea, a few being oceanic, but most of them are littoral 
forms ; some live in freshwater, while a small number are even enabled to maintain 
their existence, for a time at least, in a moist atmosphere. In the present epoch 
the tribe of the Hotostomara does not equal in number that of the StpHono- 
sToMaTA, having, as already stated, had its maximum of development in former 
geological periods. 
XXII. Family,—MELANIIDA. 
Sub-families,—MELANOPSINA, MELANIINZ, STREPOMATINA, and PALUDOMINE. 
H. and A, Adams, Genera I, p. 293; Metanrap#, Gray, Guide, 1857, p.- 101; Chenu’s 
Man. I, p. 268; mazANiANA, Lam., Deshayes, Paris foss., 2nd edit., vol. ii, p. 441. 
Dr. Brot,* who has made the family of the Melanie his special study, unites 
in it all the ¢wrbinate freshwater shells, which have the margins of the aperture not 
united, and possess a horny, spiral, or concentric operculum. The same author retains 
only the following genera, Paludomus, Swain. (incl. Tanalia, Ganga, and Philopota- 
mis); Leptowis, Raff.; Melania, Lam.; fo, Lea; Melanopsis, Fer.; Hemisinus, 
Swain.; Gyrotoma, Shuttlw.; Pirena, Lam. These genera could be easily arranged 
into four sub-families, those of the pazvpourva#, being specially characteristic for 
Ceylon and the East Indies; the true MELANIINA#, including the Melanias of the old 
world, the animals of which have the mantle margin fringed; the srrepomarrnz,t+ 
embracing the American species of Melania, the animals of which have the mantle 
simple, and the operculum subspiral, and at last the wxzavopsrv, the shells of 
which are anteriorly truncate or emarginated. 
Many of the sub-genera quoted by H. and A. Adams, Chenu, Tryon, and others, 
seem to form desirable sub-divisions in these sub-families, while others, like Lionella, 
are justly considered as doubtful, and probably not belonging to this family at all. 
True Mzranup# are first known from the ‘Wealden’ with certainty, though 
some of the species from the coal-beds of the lower Jurassic formations may be 
still earlier representatives. The characteristic fossils of the freshwater deposits 
of the cretaceous formations are as yet very imperfectly known. Some additions 
may, however, be soon expected from the latest researches of Hebert, Vilanova, 
Verneuil and others in the Western Alps and in Spain. 
For the present I am acquainted only with the small number of species des- 
cribed by myself from a cretaceous freshwater deposit in the North-eastern Alps 
(vide Sitzb. Akad. Wien, 1860, Vol. XXXVIII, pp. 483, etc.), including some 
* Catalogue systematique des especes qui comp. la fam. des Melaniens, Genéve, 1862. 
+ Vide Haldeman on S7rzPomaTIDz, etc., in Proc. Acad. Nat. Sc. Philadelphia, 1863, p. 273, and Tryon, 
dbidem, p. 306, etc.,—also Gill, in Proc. Phil. Acad. 1863, p. 34, proposing a new genus Faunopsis in the fam. 
MELANOPSIDZ, and Lea, ibid. 1864, p. 2, proposing a new genus under the name of Meseschiza. 
