374 VIEW OF THE FAUNA OF BRAZIL 



panied, at the end of each family, with the observations 

 they more immediately called forth, I presume to direct the 

 Society's attention to the general considerations that natu- 

 rally arise respecting the peculiarities of that ancient fauna, 

 and its relation to the present. Of the four orders into 

 which mammals are divided, we find on this continent repre- 

 sentatives both in the former and modern period. The most 

 numerous of these orders, as well for genera as species, is 

 now that of Myoidea ; next to which follows that of AcleU 

 dota, then Bruta, and last of all Quadrwnana. This rela- 

 tive proportion in the orders, with regard to their contents 

 of genera and species, was not the same formerly, as it is 

 now. The order Acleidota was the most numerous; next 

 followed Myoidea, then Bruta, then Quadrumana, as the 

 following table will more clearly show : — 



This change in the relative richness of the orders is occa- 

 sioned principally by the appearance in the latter period of 

 the numerous family of Bats ; which, as far as our re- 

 searches have gone, appear not to have existed in the fossil 

 period. 



Of the sixteen families into which the four orders of 

 mammals are subdivided, nine are now found in this di- 

 strict, namely, the Myrmecophaga, Armadillo, Ruminants^ 

 Pachydermata, Ferce (predatory beasts). Marsupials, Bo- 

 dents, Bats, and Apes, Of these nine, one is hitherto want- 

 ing to the list of the families belonging to the extinct 

 Fauna, in like manner as one that played a conspicuous 

 part formerly, the Sloth, is no longer found in these parts. 

 Again, with regard to the comparative richness of the other 

 families, the two periods -do not entirely agree ; as far, at 

 least, as we can conclude from the confessedly imperfect list 

 we as yet possess of the fossil species. In both periods the 

 family of Rodents is the most abundant, both in genera and 

 species; next to which follow Ferce ; but this latter is 

 proved to have been richer in genera, and probably also in 

 species, then than now. The most marked difference, how- 

 ever, is in the family of Ruminants, which in the former 

 period contained a much larger quotient, both of genera and 

 species, than in the modern. The same is also the case, 

 though not in so high a degree, with the Armadillos and 



