INTRODUCTION 15 



in the Oriental and Ethiopian Regions, are likewise found 

 in the 1 'a la -arctic Region. Furthermore, out of the eight 

 genera above mentioned, although they are not now found 

 in the Pahearctic Region, four of them are known to have 

 existed there during the Pliocene period. This shows, we 

 think, very conclusively that what small resemblance 

 there is between the mammals of the Oriental and Ethio- 

 pian Regions is due rather to a similarity in their origin, 

 than to any sort of direct connection between the two 

 regions. 



To sum up the subject we add a table of the numbers 

 of orders, families, and genera of mammals found in the 

 six different Regions, together with the number of genera 

 confined to them (endemic), the number of those slightly 

 transgressing the Regional borders (quasi-endemic), and 

 the number of those of wide-spread distribution in each 

 Region. In the second table these numbers have been 

 reduced to percentages, which give in some respects a 

 better idea of the relative specialisation of the mammal- 

 fauna of each Region. On examining these tables, it will 

 be seen that the Ethiopian Region stands second in point 

 of the number of genera confined to it, coming next to 

 the Xeotropical Region. 



The lists of genera from which this table has been 

 worked out are based on those adopted in Flower and 

 Lydekker's (3) standard work on mammals, with a certain 

 number of additions and corrections. In consequence of 

 this the figures in the case of the Nearctic Region will 

 not be found to exactly correspond with those quoted from 

 Mr. Allen above (2). It must also, of course, be under- 

 stood that the figures are merely approximate, and liable 

 to continual alterations as new discoveries are made. 



