OF SOUTHERN INDIA. 161 
H.and A. Adams divide the family into two genera, Cancellaria and Admete, and 
quote anumber of subgenera of the former. It is certain that the difficulty of distin- 
guishing the quoted sub-genera of Cancellaria is very great, although every one, 
who had studied the fossil forms, must have seen the necessity of some kind of sub- 
division in the genus Cancellaria. Until the distinctions in the shells have been 
supported by some differences in the organisation of the animal, it will be advisable 
to retain H. and A. Adams’ divisions as sub-geera. 
Considering the fossil forms, the following observations may be found worthy of 
notice. It will always be very difficult to distinguish between Cancellaria proper and 
Trigonostoma, unless the last name is restricted to a very few ¢ypical species only. 
Aphora may better not be separated from Merica, while this latter and Zuclia, 
Narona, Massyla, and Admete may probably for the most part be conveniently 
separated as genera. 
There are about 70 species of Cancrzzarizpz known living, and about as many 
tertiary, of which some 50 are neogene and 20 eocene. It is interesting to see that 
those forms, quoted by Adams under Cancellaria and Trigonostoma, which are at least 
five times more numerous than the others in the present seas, are in the neogene period 
about equal in number to those of the other groups (Zuclia, etc.), while in the eocene 
period they form scarcely one-third of all the known Cancerrarups, and in the creta- 
ceous epoch only about one-fifth. This shows also a development of elongated, conical, 
non-or scarcely-umbilicated forms into ventricose and largely umbilicated species, a 
tendency in part similar to that known in the family Vozurrpz and some others. 
The species which are up to the present known as Cancellaria from cretaceous 
rocks are exceedingly few, and most of them rather doubtful, being known only 
from imperfect specimens. 
Cancellaria. 
1. Cane. obtusa, Binkh. (Mong. Gast. et. Ceph. 1861, p, 5, Pl. II, Fig. 2) belongs to the type 
of Merica, Adams, having a solid columella and the anterior termination of the aperture 
barely notched. 
2.? Cane. reticulata, Binkh. (ibid. p. 66, Pl. V7?, Fig. 8) remains doubtful, not allowing 
even the determination of the family with certainty. This and the previous species are 
from the upper cretaceous deposits of Limbourg. 
3. Cane. Alabamensis, Gabb (Jour. Acad. Nat. sc. Phil. Ser. IT, 1860, IV, p. 301, Pl. 48, Fig. 14). 
4, Cane. Eufaulensis, Gabb (ibid p. 390, Pl. 68, Fig. 8) ; imperfectly known; Gabb does not 
mention even any co!umellar folds, neither are they apparent in the figure. 
Turbinopsis, Conrad, 1860. (Jour. Acad. Nat. sc. Phil. Ser. IT, vol. IV, p. 289). 
5. Turbinopsis Hilgardii, Cony. (ibid Pl. XLVI, Fig. 29). 
6. Turb. (Cancelluria) septemlirata, Gabb (Proc. Acad. Nat. se. Phil. 1860, p. 94, Pl. I, Fig. 10). 
If there actually be only one columellar fold present the genus Turbinopsis ought 
to be separated from Cuncellaria, as there are no such forms to be met with among living 
Cancellarie. It has been proposed by Conrad for the former species and the author 
states, that there appear to be two or more species of this genus in the eretaceous 
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