268 CRETACEOUS GASTROPODA 
like the rest of the surface of the shell. The aperture is roundish, both the margins 
being rather thin, and the inner one angulated towards the termination of the 
columella. 
The more elongated form and stronger spiral suleation distinguish our Indian 
fossil from Litt. decussata, Desh. (Mem. Soc. Géol. France, ler. Ser., Vol. V, 
pl. 17, fig. 6), which it otherwise ereatly resembles. There is no other creta- 
ceous species known, with which it can be compared. I must make an exception 
of those two species, for which Meek proposed the name Spironema, as I cannot 
make out the distinctive characters of that genus. 
Locality.—N. of Odium, in a brown calcareous sandstone ; only two specimens 
have as yet been found. 
Formation.—Ootatoor group. 
XXXI. Fumily—AMPHIBOLID4, vide H. and A. Adams’ Gen. II, 
p. 268. 
XXXII. » —VALVATIDA, ibid., I, p. 348, (Valvata and Lyogyrus, ° 
Gill, Proc. Amer. Phil. Acad., 1863, p. 34). 
XXXII. » —AMPULLARIIDA, ibid., I, p. 344. 
XXXIV. » —VIVIPARIDZ,® ibid., p. 337. 
XXXYV. » —RISSOLLLID 4, ibid., p. 325. 
Of these five families no representatives have as yet been found in our cre- 
taceous rocks of South India. A few species of Viviparus, Bythinia, a. oth., have 
been described from the Wealden beds, but no such forms have as yet been 
reported from the cretaceous formations in general, though they most probably 
were not wanting in the fresh waters, which existed during that period. 
With regard to the family zssozzzip2, it is worthy of mentioning, that 
Deshayes lately established in his new edition of the Paris fossils (Vol. II, p. 383,) 
anew genus, Lacunella, for a species generally agreeing with Lacuna, the shell of 
which is, however, thin and pellucid.. This structure of the shell combined with 
its form could scarcely be compared with any other recent species, than those of the 
family Rrssozri1p#, to which it probably belongs. Hyala, placed by H. and A. 
Adams in this family, is stated to have more affinities with dclis, and we shall 
mention the genus again, when speaking of the sub-family cuzuyirzuna of the 
EULIMIDZ. 
* Gill (Arrangement etc., fam. Virrparip# (Proc. Phil. Acad., 1863, p. 33, etc.) quotes four genera as 
constituting this family, Twlotoma, Haldeman, Viviparus, Lam., Melantho, Lea, and Lioplax, Troschel. Meek 
proposes for the jurassic species Mel. (Potadoma) veterna, Meek and Hayd., a new generic name, Leioplacodes 
(Smith. Misc. Coll. No. 177, 1864, p. 40); and Conrad has in the Viyrpakipz a new genus Campeloma (Smith. 
Mise. Coll. No. 200, 1866, p. 12). Paludomus and Tanalia are referred to the Mzranip# ; and Bithinia and 
Stenothyra (Nematura, olim) to the Rissorm#, The genera Larina, A. Adams, (a thin Amphibola—hke shell,) 
and Rivulina, Lea, are added to the Viyiparip# in H. and A. Adams’ Genera II, 624-625. See also Larina 
Burmana, Blanford, in Journ, As. Scc., Bengal, for 1867, p. 61, pl. 18, fig. 1. 
