606 



Original Articles. 



[Oct., 



In the present endeavour to put forward the general aspects of 

 the Mammal-fauna of this region in a somewhat more decided 

 light than has yet been attempted, I shall proceed to discuss the 

 forms of the different orders of terrestrial Mammals that are found 

 within its area, one by one. Summarizing the results thus arrived at, 

 we shall not find it difficult to realize the principal characteristic 

 features of Neotropical Zoology as regards this order of Vertebrates. 



The American Monkeys, as universally allowed by Zoologists, 

 form a strongly-marked division of the order Quadrumana, so dis- 

 tinct from the corresponding forms of the Eastern Hemisphere as 

 not to be possibly confounded with them. They are spread over 

 nearly the whole of tropical America, on the eastern side of the 

 Andes, from the tierra caliente of Southern Mexico* to the most 

 southern woodlands of Brazil and Uruguay. To the west of the 

 Andes I am not aware that the presence of Quadrumana anywhere 

 south of the Bay of Guyaquil has yet been recorded. The American 

 Quadrumana are divisible into two well-marked sections, which 

 perhaps deserve the rank of families. The Cebidas, which are the 

 most highly organized of the two divisions, are at once distinguish- 

 able from the Simiidae of the corresponding latitudes of Africa and 

 Asia by the presence of thirty-six teeth, instead of thirty-two ; the 

 false molars being increased from eight to twelve in number. The 

 Marmosets (Hapalidae), which take a lower rank, have the same 

 total number of teeth as the Old World Simiidae, but four fewer 

 true molars, this difference being made up by a proportionate increase 

 in the number of false molars — which, as in the Cebidae, are twelve in 

 number. The subjoined table will give at a glance the distribution 

 of the generally-recognized families of the Quadrumana amongst the 

 seven principal Zoological Regions of the earth's surface. 



1. 



Neotropical 

 Region. 



2. 



Neakctic 

 Region. 



3. 



Pauearctic 

 Region. 



4. 



^Ethiopian 



Region. 



5.f 

 Lemurian 

 Region. 



6. 



Indian 

 Region. 



1. 



Australian 

 Region. 



Cebidse 

 Hapalidse 





Simiidse 



SimiidEB 

 Lemuridae 



Lemuridse 

 Chiromyicte 



Simiidse 



Lemuridse 

 Tarsiidee 





A few words may now be said concerning the principal genera which 

 compose the two families of American Quadrumana. It may be 



* For some remarks on the northern limit of the Quadrumana in the New 

 "World, see 'Nat. Hist. Kev.,' 1861, p. 507, where I have endeavoured to show 

 where the line should be drawn with more exactitude than has hitherto been done. 



t I have hitherto only reckoned the principal Zoological Regions of the earth, 

 as six in number, having associated Madagascar and its islands with Africa. 

 The peculiarities of the Zoology of Madagascar and the Mascarene Islands are, 

 however, so great, especially as regards its Mammals (see my former article on this 

 subject, ' Journ. of Sc.,' vol. i. p. 213), that it is perhaps better to consider them as 

 forming a distinct Zoological Eegion, for which no term can be more appropriate 

 than that of Lemur ia, as has been already suggested I. c. 



