OF SOUTHERN INDIA. 273 
1. Truncatella, Risso, 1826, (Adams’ Gen., II, p. 310). The species live 
usually under wet grass on the sea coast. Deshayes, who describes several eocene 
species in his new edition of the Paris fossils, also places this genus in the Rrssorpz#. 
2. Tuaheitia, H. and A, Adams, 1863, (Ann. Mag. Nat. Hist., XI, p. 19,) is a 
Truncatella with a shelly operculum. 
3. Cecina, A. Adams, 1861, (Ann. Mag. Nat. Hist., VIII, p. 308,) only 
differs from Truncatella in having the surface of the shell smooth, and the outer lip 
somewhat produced near the middle. 
4. Tomichiu, Benson, 1851, (Adams’ Gen., II, p. 313,) is founded upon a shell 
resembling the last; the animals are also alike, except that the bulgings of the eyes 
are somewhat more distinct. Species of Zomichia have been found in South Africa, 
India and Japan, (vide A. Adams in Ann. Mag. Nat. Hist., 1861, VIII, p. 808). 
5. Blanfordia, A. Adams, has been separated for species like Tomichia Bensoni 
and Japonica. The shells are chiefly distinguished from those of true Tomichie by 
the thickened margins of the aperture and by the outer lip, which is externally 
sub-varicose. 
6. Geomelania, Pfeiffer, 1845, (Gen. II, p. 311,) are said to be more terrestrial 
‘than Truncatella, which they otherwise very much resemble. The species are 
principally inhabitants of the island of Jamaica. 
7. Chittia, Livesay, 1858, (Adams’ Gen., IT, p. 647,) differs from Truncatella by 
a posterior insinuation of the outer lip. Deshayes describes an eocene species under 
the name of Aciculina emarginata, (Paris foss., 2nd. ed., II, p. 533, pl. 25, figs, 25-27). 
8. Micropyrgus, Meek, 1866, (Conrad in Smithsonian Mise. Coll., n. 200, 
Check list of eocene fossils, p. 12). Shell minute, smooth, sub-cylindrical, with 
obtuse apex and rhombic aperture; the type is Mel. minutula, Meck and Hayd. 
(Proc. Acad, Nat. Sc., 1856), which was found fossil in association with fresh-water 
shells. It is probable that the genus belongs to this sub-family. 
e. Sub-family,—SKENEIN 4. 
Stimpson only places in this sub-family Skenea, Fleming, (H. and A. Adams’ 
Gen. I, p. 385,) but it is very probable that Adeorbis, Wood, 1842, (ibid. p. 407) 
has to be classed in the same. Deshayes says in his last edition of the Paris 
fossils, that the animal of Adeorbis is not essentially different from that of Rzéssoa. 
Some other species referred to Lrorip. also show great similarity, in the structure 
of their shells, to those of this sub-family. 
f. Sub-family,—RISSOLN Ai. 
The following genera, which are mostly marine and largely represented in a 
fossil state, belong to this division :— 
1. Setia, H. and A. Adams, 1854, (Gen. I, p. 333). 
2. Cingula, Fleming, 1828, (ibid. p. 334). 
3. Ceratia, H. and A. Adams, 1854, (ibid. p. 333,) has the tentacles flat and 
short, like most of the wyprozuvs, but the foot has appendices like other 
rissoiva#. ‘The shell is thin, but distinctly spirally striated. 
3x 
