THE CHINCHILLA. 
9 
outer there is no indication of such a division ; the 
inner surface of each of these teeth consequently offers 
two such grooves, while the outer presents no more 
than one. 
In the observations appended to his account of the 
teeth Mr. Yarrell appears to consider the Chinchilla as 
nearly allied to Mr. Brookes's new genus Lagostomus, 
of which a figure and description are contained in the 
last published part (the first of the sixteenth volume) 
of the Linnean Transactions ; and the general resem- 
blance of form, together with the characters of the 
teeth as given in that notice, unquestionably warrant 
at least a close approximation. But we apprehend that 
the alteration above made in the description of the 
teeth of the Chinchilla, together with the discrepancy 
in the number of the toes, which in our animal are four 
on the hind feet, while in Lagostomus they are but 
three, will be considered fully sufficient to establish a 
generic difference between them. The close affinity 
subsisting between these animals has been subsequently 
recognised by M. Cuvier from the very imperfect mate- 
rials in his possession, consisting only of mutilated 
skins of the one and drawings and descriptions of the 
other. In the new edition, just published, of his Regne 
Animal he regards them both as decidedly forming 
part of the same genus ; but does not venture, until he 
shall have seen their teeth, to determine their position, 
in the series, which he considers so uncertain as to 
render it doubtful whether they approach most nearly 
to the Guinea-pigs, the Lagomys, or the Rats. In the 
removal of these doubts we are happy to assist by 
furnishing the proof that, although generically distinct, 
they both evidently belong to the same natural tribe, 
and contribute, along with Lagomys and Pedetes, to 
establish a connexion between the otherwise widely 
separated families of the Hares and the Jerboas. 
