PREVIOUS TO THE LAST GEOLOGICAL REVOLUTION. 309 



in the diluvian soil ; on the other hand, I have discovered 

 bones of a small and evidently rodent animal, which does 

 not agree vs^ith any of the genera at present existing in this 

 country. 



The caves contain abundant fossil remains of the genera 

 Lepus and Anooma ; and still more of a species belonging to 

 the genus Dasyprocta ; all of which resemble more or less 

 closely the recent species of their respective genera. There 

 is, however, a second species of the last-named genus which 

 merits a particular notice, not merely from its much greater 

 rarity, but from its extraordinary size, which at first misled 

 me in the identification of its bones. The long bones of the 

 hinder extremities of this species are, in fact, almost as large 

 as those of the roebuck, for which reason I propose for it the 

 name of Dasy, capreolus, in order to connect with its spe- 

 cific title an idea of a size so unusual in this family. 



The same relation which we have observed in the genus 

 Cutia, is repeated in the genus Capivar. I find two extinct 

 species of this genus ; the one identical with that now existing, 

 the other, on the contrary, of astonishing size. I propose 

 for this last, the name Hydrochcerus sulcidens, because its 

 incisors, instead of being smooth, as in the living species, 

 are furnished on their anterior surface with a number of lon- 

 gitudinal furrows, separated by parallel, rifle-like ridges. It 

 approached the very considerable dimensions of five feet in 

 length, so as to stand exactly midway between the existing 

 species of this genus, and the giant of South America's recent 

 fauna, the tapir. 



I conclude my brief survey of this family with a genus 

 that requires a more detailed examination than the former, 

 on account of the important light it throws upon the ancient 

 fauna, and its relation to the recent ; I mean the genus Paca. ' 

 The remains of this genus, in a fossil state, are found in the 

 soil of most of the Brazilian caves : I have endeavoured, in 

 my description of that of Cerca Grande, to convey some idea of 

 the astonishing extent to which they are there amassed. A 

 cursory examination of these remains showed me no essen- 

 tial difference from the recent Paca. We have already, in 

 our survey of the previous families, met with fossil remains 

 that seemed to agree more or less accurately with existing 

 animals, but whose complete identity we were prevented from 

 determining by the imperfect state of the fragments. But it 

 is particularly in the family now under review, that this diffi- 

 culty so frequently occurs ; the genera Echimys, Anwma, 

 LepiiSf and Dasyprocta, have furnished examples of this. 

 What has thus occurred to myself in the determination of the 



' Coelogenys. 



