348 CRETACEOUS GASTROPODA 
to be proved. Nor do I think it very probable, that most of those little shells, 
for which Fischer proposed the name Psewdorotella, are very different from Teimos- 
toma and other similar forms. Fischer’s characteristic (Journ. d. Conch., 1857, VI, 
p. 52) of Pseudorotella runs as follows: shell thin, transparent, globose or flattened ; 
whorls few, finely striated ; wmbilicus covered with a transparent callus; shining ; 
peristome not continuous; outer lip arcuated, simple, sharp. The typical species is 
Pseudor. semistriata, D’Orb. 
We here retain the genus for the umbilicated species only. Teinost. Grignonense, Desh. (Paris _ 
fossils, 2nd edit., pl. 63, figs. 830-32) is in this sense to be considered as a Vetrinella. - The only 
cretaceous species which we know is from the Verdachellum deposits at Pondicherry, Vitrinella 
orbiculata, n. sp. 
?9. Umbonelia, A. Adams, 1863 (Ann. mag. nat. hist., XI, p. 265); shell 
globose subconic, solid, porcellanous, polished, with a narrow umbilicus ; aperture 
subquadrate, inner lip anteriorly expanded, margin of the umbilicus crenulated. 
A. Adams considers the Turbo murreus (Reeve, Conch. Icon. Monog. Turbo, 
species 54, pl. 12,) as the type of the genus. This species does not appear to differ 
generically from Margarita, unless its sole character is placed in the smooth and 
polished surface, on which account, I presume, it has been referred by A. Adams 
to the family Umronipz. 
10. JLsanda, H. and A. Adams, 1854 (Gen. I, p. 409); shell subconic, smooth, 
porcellanous ; aperture subquadrate, inner lip straight, margin of umbilicus crenu- 
lated, outer lip thin. 
There are a few tertiary species known, which may belong to this genus, but 
I do not know any from secondary or older deposits. 
11. Calceolina, A. Adams, 1863 (Ann. mag. nat. hist., XI, p. 267), founded 
upon Neritina pusilla of C. B. Adams. The shell is characterised by its depressed 
and oblong form, short spire, rapidly increasing whorls, and the umbilicus covered by 
a callus. 'The aperture is semicircular, not pearly within; the inner lip is covered 
by a large callus, which spreads over the umbilicus, the anterior margin of the 
aperture being almost straight. 
There are several similar little shells to be found in the eastern seas; they 
very much resemble Neritine in general form, but have the inner lip somewhat 
produced. in the middle without any teeth on the edge of the same. The surface is 
smooth and polished. A. Adams does not describe the form of the inner lip of the 
so-called Calceolina sufficiently, to enable his shell to be identified with accuracy. 
12? Microthyca, A. Adams, 1863 (Ann. mag. nat. hist., XI, p. 265), has 
been proposed for a subturbinate species, WZ. crenellifera, the shell of which is 
subporcellanous, spirally ribbed ; aperture semicircular, with continuous margms, 
both being thickened and the umbilicus crenulated. The position of this genus in 
the Usmsonmpx appears to me rather doubtful ; it seems almost quite as probable 
that it belongs to the Lzormpz. 
18, Crossostoma, Morris and Lycett, 1850 (Moll. Great Oolite, pt. I, p. 72) ; 
shell subturbinate, smooth ; aperture round, with the margins united, externally thick- 
ened and expanded ; umbilicus entirely covered with callus. 
