OF SOUTHERN INDIA. 383 
Lias under the name of Zrochotoma (Sitz. Akad., Wien, 1861, XLIII, p. 193), 
but I rather believe now that those anomalies are most probably due to accidental 
injuries of the slit, and are in any case not constant. The tertiary Pl. Sismondai, 
Goldf. (Petref. Germ. III, pl. 188, fig. 1), from Bitnde is a Leptomaria and 
probably also the two species described from the tertiaries of Italy. Pl. concawva, 
Desh., from the Paris basin appears to represent a new type, for although it has 
a very narrow and deep slit, its form, ornamentation and the character of the 
margins of the aperture are very different. 
The two recent species are in form allied to Leptomaria, but they have a 
much wider band and a short slit and consequently belong to Pleurotomaria 
proper. 
7, Scissurella, V@Orb., 1828 (Sorssurezzip#, Gray ; Deshayes, Anim. s. vert. 
foss. bass. de Paris, 1866, III, pp. 1-7; Anatomus, Montf., H. and A. Adams, Gen. I, 
p. 489, and others). Shell orbicular or depressedly conical, thin, widely wmbi- 
licated, internally not (?) pearly, outer lip with a short slit continuing as a band 
on all the previous whorls, inner lip of the aperture thin, outer lip at the base 
broadly insinuated. Setting aside the size of the shell it must be agreed that 
some of the widely umbilicated species of Plewrotomaria are externally not to be 
distinguished from Scisswrella, and have most probably to be referred to this 
genus, for I do not think that the nacreous internal layer of the shell of Scissurella 
is perfectly wanting. The typical Pleurotomarie always have the inner lip some- 
what thickened, while those of Zeptomaria have it thinner and, like the narrow 
band, more similarly formed to that of Scissurella. 
With reference to Montfort’s name Anatomus, Deshayes’ latest arguments must. 
be considered as conclusive, namely, that Montfort could not have described a shell of 
Scissurella ; and as that author’s reference to the figures in Soldani’s work do not 
apply to Scissurella (which has been figured in the same work) but to Spirorbis 
(perhaps Cryptobia of the Szzrevarips#:) the name Anatomus must not be used 
in place of that of Scissurella. 
There are at present about 26 recent and some six or seven tertiary species 
known; the mesozoic ones have as yet to be discriminated. 
8. Polytremaria, dOrb., 1850 (Prodrome, I, p. 122), proposed for the carbo- 
niferous species P. catenata, Kon., being a trochi-form shell with the band 
composed of numerous small perforations, somewhat like in Haliotis. 
9. Trochotremaria, Ryckholt, 1860 (Journ. Conch., IV, p. 186), is said to be 
a turbinate shell with an obliterate band, showing a number of round perforations ; 
two or three of these being always open; the species are carboniferous. 
10. Catontostoma, Sandberger, 1842. The only species as yet known is 
Cat. clathratwm from the paleeozoic (devonian or carboniferous ?) rocks of the 
Rheinlande. According to Suess who was the first to give a correct characteristic 
of the species the shell is ovate, rather solid, composed of numerous convex 
volutions, the last of which is towards the aperture deflexed, this being oval, with 
the margins united, having the inner and outer lips almost parallel; a distinct band 
