MR. E. T. BENNETT ON THE CHINCHILLID. 63 
Kerodon, and Dolichotis,) were absolutely unknown, in a zoological sense, only twelve 
years ago. Two of these, Chinchilla and Lagotis, were first fully described from speci- 
mens contained in the Menagerie and Museum of this Society ; of a third, Octodon, the 
only account yet extant is derived from the same source ; and to the history of two 
others, Capromys and Ctenodactylus, most important additions have been made from 
the examination of individuals formerly living in our Gardens. 
In a department which has afforded, during so short a period, so many additions to 
science, it is reasonable to anticipate, and probably for many years to come, repeated 
and almost continual accessions. In various parts of the world which are comparatively 
well known, the Rodentia are far from being exhausted as objects of zoological inquiry ; 
and the vast continents of Africa and America (the latter, especially in its southern 
half, apparently the metropolis of the order,) have hitherto, perhaps, furnished us with 
only a foretaste of what may be expected from them, when their interior shall be opened 
to the investigations of active and informed travellers. To the materials which will 
doubtless be collected by the zeal and enterprise of such men we must look for the 
means of correcting and completing the confessedly imperfect sketch of the Herbivorous 
portion of the order, which I have ventured to submit to the consideration of the 
Society. 
PLATE IV. 
Lacoris Cuvier. 
PLATE V. 
Fig. 1. Stomach of Lagotis Cuvieri. 
2. Cecum of Lagotis Cuviert. 
3. Stomach of Chinchilla lanigera. 
4. Cecum of Chinchilla lanigera, less distended than that of Lagotis. 
PLATE VI. 
Skeleton of Lagotis Cuvieri, two thirds of the natural size. 
Fig. 1. Cranium seen from above. 
2. Cranium seen from below. 
3. Lower jaw seen from above. 
4. Crowns of the two anterior molar teeth of the lower jaw, enlarged. 
5. Crowns of the two posterior molar teeth of the upper jaw, enlarged. 
