312 CRETACEOUS GASTROPODA 
do, for instance, Assiminea, Truncatella, Tomichia, and others to the Rzrssorpa, that 
is, they seem to be forms which are undergoing a change from BRANCHIFERA into 
PULMONIFERA. 
My present remarks will be restricted only to a few genera of the true 
VELUTINIDE. 
1. Naticina, Gray, 1842 (H. and A. Adams, Gen. I, p. 211). Shell ovate, 
with moderately elevated spire, thin, last whorl ventricose, surface spirally striated ; 
aperture large, outer lip sharpened, inner lip a little thickened, occasionally leaving a 
slight fissure exposed at the termination of the columella. 
H. and A. Adams class this genus next to Sigaretus (Catinus) in the Naricipz, 
but A. Adams states subsequently (Ann. Mag. Nat. Hist., 1860, VI, p. 109) that 
it ought to be placed in the Vzzurrvip~. The only cretaceous species, which has 
as yet been described, is Naticina obliqua, Gabb (Pal. Calif., 1864, I, p. 109, 
pl. 21, fig. 112), from the Californian deposits ; this species has rather a wide aperture 
more resembling a Sigaretus. I shall describe from our South-Indian rocks another 
species which, although based upon a rather imperfect specimen, the shell being 
only partially preserved, is from its general appearance most probably another 
cretaceous representative of this genus. 
2. Lysis, Gabb, 1864 (Pal. Calif., I, p. 188). “General form like Stomatia 
(=Sigaretus). Shell sub-spiral, very oblique; spire moderately prominent; whorls 
spirally costulated. Aperture narrow, oblique ; outer lip simple; columellar lip 
straight and rather heavily incrusted. Umbilicus broad, but entirely closed by a 
concave expansion of the incrusting layer of the inner lip.” 
Gabb describes one species, L. duplicosta, from the cretaceous rocks of Cali- 
fornia; it appears to be rather a thin shell, principally differing from Naticina by 
the great thickness of the inner lip which covers the umbilical region. 
3. <Amplostoma, Stoliczka, 1868. 
Ampl. testa sub-ovata, tenuwi, spira brevt ; anfractibus paucis, ultimo maxino, 
ventricoso, antice valde producto, ad basin late-excavato ; apertura elongate-ovata, 
antice atque postice sub-angulata, labio tenui, labro ad marginem dilatato, expanso 
atque reflexo ; superficie sub-levigata. 
This genus is based upon a remarkable species from our cretaceous deposits ; it 
very much resembles in form a Swecinea, but is widely umbilicated, and has the 
outer lip expanded and reflexed. From Velutina it differs both by the large 
umbilicus and by the expanded outer lip. Both this and the last named genus 
very much remind one of some forms of Coralliophila (rapayina), in which the 
anterior canal is sometimes very indistinct. 
We only know as yet the cretaceous Amp. auriforme, which will be noticed 
subsequently. There is, however, a Littorina macrostoma described by Sandberger 
from the Stringocephalus-limestone of Villmar (Rhein. Schichtensystem, etc., p. 221, 
pl. 25, fig. 16), which in all its principal characters agrees with our Amplostoma 
and most likely belongs to this genus. Deshayes describes from the Paris basin 
under the name of Sigaretus problematicus a minute shell, which in general form 
