COMMON RHEA 231 
before the appearance of the European mounted 
hunter, enables it to see far; its dim grey plumage, 
the colour of the haze, made it almost invisible to 
the eye at a distance, the long neck being so slender 
and the bulky body so nearly on a level with the tall 
grasses ; while its speed exceeded that of all other 
animals inhabiting the same country. When watching 
the chase of Ostriches in the desert pampas, abound- 
ing in giant grasses, it struck me forcibly that this 
manner of hunting the bird on horseback had brought 
to light a weakness in the Rhea—a point in which 
the correspondence between the animal and its en- 
vironment is not perfect. The Rhea runs smoothly 
on the surface, and where the tall grass-tussocks are 
bound together, as is often the case, with slender 
twining plants, its legs occasionally get entangled, 
and the bird falls prostrate, and before it can struggle 
up again the hunter is close at hand and able to 
throw the bolas—the thong and balls, which, striking 
the bird with great force, wind about its neck, wings, 
and legs, and prevent its escape. When I questioned 
Ostrich hunters as to this point they said that it was 
true that the Rhea often falls when running hotly 
pursued through long grass, and that the deer 
(Cervus campestris) never falls because it leaps over 
the large tussocks and all such obstructions. This 
small infirmity of the Rhea would not, however, 
have told very much against it if some moderation 
had been observed in hunting it, or if the Argentine 
Government had thought fit to protect it; but in 
La Plata, as in North America and South Africa, the 
