20 THE SPECIES OF RHEA. [CH. I 



sufficient for the purpose. Rh. darwini and Rh. americana 

 agree to differ from Rh. macrorhyncha in having only 15 

 (instead of 16) cervical vertebrae and in having a broad 

 skull. They differ from each other principally in the fact 

 that the metatarsus in front has scutes on distal half only 

 in Rh. darwini; Rh. macrorhyncha agreeing with Rh. 

 americana in having transverse scutes along the whole 

 length of that part of the leg in front. 



The range of the three is as follows : — Rh. americana 

 extends from Bolivia through Paraguay into Uruguay 

 and southward to the Rio Negro. Its head-quarters seem 

 to be the pampas of Argentina. 



Rh. darwini is restricted to the eastern half of 

 Patagonia and to south-eastern Argentina. It overlaps 

 the last species about the Rio Negro. 



Finally Rh. macrorhyncha occurs in the provinces of 

 Pernambuco and Bahia but does not overlap Rh. americana. 

 Dr Gadow intimates that on the whole Rh. darwini is the 

 best marked species. Hence possibly its overlapping is 

 less remarkable, since the greater difference in organisation 

 may go with a greater difference in habits. 



Distribution of Ibexes. 



There are altogether eleven species of Wild Goats as 



allowed by Mr Sclater 1 , to which may be added a twelfth 2 . 



(1) Copra pyrenaica, the Spanish Ibex, is not only 



Pyrenean, but is found, slightly altered in character, in the 



mountain ranges of other parts of Spain and Portugal. 



1 P.Z.S. 1886, p. 314. 



2 There are probably however more names than species. 



