Mr. Bennett on the Chinchillida. 493 
Of Lagostomus, as I have before observed, Dr. Meyen enumerates 
three species. The two first of these represent the animals respectively 
figured by the late Mr. Brookes and by M. Lesson under the name of 
Lagostomus trichodactylus, which he considers as distinct on account of 
the differences observable between the two figures. These consist in the 
small and curved claws of the hinder foot in the former, contrasted with the 
large size and nearly straight direction of the same organs in the latter ; in 
the habit; and in the shape of the tail. The misapprehension is undoubtedly 
very excusable; but it may serve to shew how dangerous it is to rely on 
figures only in the discrimination of species. As regards the first pre~ 
sumed distinction, I have already observed (p. 57 of my paper) that 
‘‘ in this particular the figures given by Mr. Brookes are defective, as 
exhibiting the claws far smaller and more curved than is natural.” A 
reference to the descriptions of M. F. Cuvier and M. de Blainville, both 
taken from Mr. Brookes’s specimen while living, will confirm the. 
accuracy of this observation; the latter in particular (Desm. Mammal. 
No. 508) describing the middle toe of the hinder foot as furnished with 
avery strong claw. On the second point, the habit, it need only be 
observed that both figures were taken from stuffed skins by artists who 
had never seen the living animal ; and who could consequently give only 
their own conjectural ideas of its natural appearance when in a living 
state. On the third, it may be observed that some obscurity is to be 
feared, M. de Blainville having described the animal while living as having 
its tail truncate and mutilated, and Mr. Brookes’s skin and skeleton 
being both provided with perfect tails. I may add that a fine skin now 
in the possession of the Zoological Society agrees in all essential particu~ 
lars with the animal figured by M. Lesson, and as far as my recollection 
goes, with that which formerly formed part of Mr. Brookes’s Museum. 
The figure given by the latter should only be considered correct in so far 
as it is borne out by the descriptions of MM. F’. Cuvier and de Blainville, 
which should be referred to in connexion with it. 
The third species of Lagostomus enumerated by Dr. Meyen is the 
Eriomys Chinchilla of Dr. Lichtenstein, figured and described in that 
