RHEAS. 
remainder of the under-parts are dirty white. The iris of the eye is pearl-grey, 
the naked portion of the skin flesh-coloured, the beak horn-brown, and the leg 
grey. In the female the feathers of the nape and front of the breast are somewhat 
lighter in hue. The place of the ordinary species is taken in Eastern Patagonia by 
the far less common Darwin’s rhea {11. darwini), distinguished by its smaller size, 
relatively shorter legs, which are feathered down to the ankle-joint, as well as by 
the more mottled and 
less uniformly coloured 
plumage, and the pale 
green eggs. Lastly, we 
have the long - billed 
rhea ( R. macrorhyncha ) 
of Northern Brazil, 
which is also a small 
form characterised by 
its longer beak, larger 
and more flattened head- 
feathers, the longer 
feathers of the body, 
and the more slender 
legs, as well as by the 
general darker colora¬ 
tion, which is brownish 
grey mingled with black. 
Fossil remains of rheas, some of which belong to existing species, are met w T ith in 
the caverns of Brazil and the superficial deposits of other districts of South America. 
In general habits, rheas, although somewhat more gregarious, are 
very similar to ostriches, and as thoroughly adapted for a life on 
the South American pampas as are the latter for existence in the South African 
veldt and karru. As a rule, each cock rhea associates with from five to seven 
hens, which he carefully guards from the attentions of other members of his 
kindred; although after the breeding-season such family-parties collect together 
in flocks, which may reach a total of sixty or more head. Possessed of a speed but 
little inferior to the ostrich, the rhea is further protected by the exactness with 
which the general pale bluish grey hue of its plumage assimilates to the distant 
haze, thus rendering it invisible even at a moderate distance. Its large form seems, 
indeed, as Mr. W. H. Hudson remarks, to melt mysteriously out of sight into the 
surrounding blue, so that the hunter strains his eyes in vain to distinguish it. 
A truly noble bird when standing among the tall grasses of its native 
pampas, the cock rhea* summons his scattered consorts by a hollow booming 
cry, probably not unlike that of the ostrich, accompanied by a kind of sighing 
or hissing sound. When running from their pursuers, both sexes have the 
curious habit of raising one wing above the back in a sail-like fashion. In 
hot weather these birds will take readily to the water, not only standing in it 
with their bodies submerged, but also swimming boldly, though slowly, with 
their necks bent slightly forward and scarcely showing any portion of their 
VOL. iv .—36 
HEAD OF LONG-BILLED RHEA. 
(From Sclater, Proc. Zool. Soc., 1860.) 
