348 MamMatia OF INDIA. 
the second division consists of three sub-genera with rootless molars, viz. 
Paludicola, Agricola, and Arvicola, which last has again been subdivided 
into long-eared and short-eared Voles—Arvicola and Microtus — dis- 
tinguished by the former having eight and the latter four mamme, and 
respectively six and four 
tubercles on the plante, 
the ears of the latter being 
almost hidden by the fur. 
None of the forms with 
which we have now to deal 
belong to the first division, 
for, as far as the matter has 
been investigated, the In- 
dian Voles have rootless 
molars, but the character 
of the teeth in some differs 
from the European forms, 
and therefore Mr. Blanford 
has proposed a new sec- 
tion, A/¢ticola, for their reception. I have not space here, nor would it 
accord with the popular character of this work, to go minutely into all 
the variation of dentition which distinguish the different species. To 
those who wish to continue to the minutest details the study of the 
Indian Voles, I recommend a most careful and elaborate paper on them 
by Mr. W. T. Blanford, F.R.S., in the Journal of the Asiatic Society 
of Bengal, vol. L., pt. il.; but without entering into the microscopic 
particulars of each species, I may here give a general idea of the forma- 
tion of the teeth of the Arvicole differing as it does so much from others 
of the myomorphic or mouse-like group of rodents. In these the general 
contour of the molar teeth is roundish oblong, the margins being wavy 
or indented, according to the convolutions of the enamel, but in the 
Voles there is a sharp angularity about these indentations ; the marginal 
lines, instead of being in well-rounded curves, are sharply zigzag, forming 
acute angles. If you were to draw two close parallel zigzag lines it 
would give you some idea of the contour of these teeth. The molars 
are in fact composed of alternating triangular prisms, with the outer 
folds of enamel forming deep and acute angles. The other charac- 
teristics of this family are: skull, with brain case rhomboidal, frontals 
much contracted ; infra-orbital opening typical ; limbs moderate ; tail 
moderate, or short and hairy. 
Dentition of Arvico/a. 
