810 VIEW OF THE FAUNA OF BRAZIL 



species of the extinct fauna of this continent, has also 

 happened to those who have been occupied in similar 

 researches in the old world ; and the important question 

 yet remains unanswered, whether in fact species identically 

 the same, can be shown as belonging to these two periods. 

 The genus now under consideration, seems likely to afford 

 a solution to this question, on at least one point. On 

 the one side, the complete identity with the living spe- 

 cies which the first view of the fossil remains of this genus 

 exhibited, seemed to authorize me to consider it in the same 

 light as those already described as coinciding more or less 

 with existing genera ; while on the other hand, the extraor- 

 dinary abundance and perfect state of the materials for 

 comparison, which I possessed of this genus, far exceeding 

 those at the disposal of any former zoologist, enabled me 

 to decide the point, so far as it referred to the corresponding 

 species of this district, with an accuracy which could not 

 leave any room for doubt or uncertainty. Two subsequent 

 visits to that remarkable cave, and long- continued exca- 

 vations, had so multiplied my materials, that I was enabled to 

 enter upon the investigation with more or less perfect re- 

 mains of above a hundred individuals, of all ages. 



The result of these examinations was equally surprising 

 and conclusive. In spite of the close correspondence in 

 every other part of the skeleton, a more exact consideration 

 of the skulls, proved that the vast number of the fossil re- 

 mains of this genus consisted of two species, both of which 

 are very distinct from the living Paca. One of these I call 

 Coelogenys laticeps, from the circumstance of the zygomatic 

 arches being posteriorly so far retired from the skull, that it 

 acquires the appearance of being pressed flat. The other 

 species I have already described under the title of Coelogenys 

 rugiceps, a name that well becomes it. In this species the 

 glenoid cavities and adjoining zygomata are so extraordi- 

 narily developed, that these same anatomical relations in the 

 existing species seem to be only a feeble indication of the 

 almost monstrous development that gives the skull of this 

 species so peculiar a character. Both these species appear 

 to have been very common in those olden times ; but much 

 rarer are the remains of a third species, Coelogenys ma- 

 jor, which considerably surpasses both the former in size, 

 and which, in this respect, is not inferior to the living Ca- 

 pivar. 



These examinations of the genus Paca, which, from their 

 completeness, may serve for the foundation of the subsequent 

 comparisons, give the same relations for this genus, that we 



