124 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



H. Darwinii. R. Americana, 

 inches inches 



Length of beak, from edge of membrane at base to the apex ... 2 2 1 



Length, from anterior margin of eye to apex ...... &fa 5^- 



"Width of upper mandible, measured across middle of nostrils . . . ly$ 1-& 



The skin round and in front of the eyes is less bare in R. Darwinii; and 

 small bristly feathers, directed forwards, reach over the nostrils. The feet and 

 tarsi are nearly of the same size in the two species. In the R. Darwinii, short 

 plumose feathers extend downwards in a point on the sides of the tarsus, for about 

 half its length. The upper two-thirds of the tarsus, in front, is covered with 

 reticulated scales in place of the broad transverse band-like scales of the R.Ameri- 

 cana ; and the scales of the lower third are not so large as in the latter. In the 

 R. Darwinii the entire length of the back of the tarsus is covered with reticulated 

 scales, which increase in size from the heel upwards : in the common Rhea, the 

 scales on the hinder side of the tarsus are reticulated only on the heel, and about 

 an inch above it ; all the upper part consisting of transverse bands, similar to 

 those in front. 



The first notice I received of this species was at the Rio Negro, in Northern 

 Patagonia, where I repeatedly heard the Gauchos talking of a very rare bird, 

 called Avestruz Petise. They described it as being less than the common ostrich 

 (which is there abundant), but with a very close general resemblance. They 

 said its colour was dark and mottled, and that its legs were shorter, and feathered 

 lower down than those of the common ostrich. It is more easily caught by the 

 bolas than the other species. The few inhabitants who had seen both kinds, 

 affirmed that they could distinguish them apart, from a long distance. The eggs, 

 however, of the small species appeared more generally known, and it was 

 remarked with surprise, that they were very little less than those of the common 

 Rhea, but of a slightly different form, and with a tinge of pale blue. Some eggs 

 which I picked up on the plains of Patagonia, agree pretty well with this descrip- 

 tion ; and I do not doubt are those of the Petise. This species occurs most rarely 

 in the neighbourhood of the Rio Negro ; but about a degree and a half further 

 south they are tolerably abundant. One Gaucho, however, told me he distinctly 

 recollected having seen one, many years before, near the mouth of the Rio 

 Colorado, which is north of the Rio Negro. They are said to prefer the plains 

 near the sea. When at Port Desire in Patagonia (Lat. 48°), Mr. Martens shot an 

 ostrich ; I looked at it, and from most unfortunately forgetting at the moment, 

 the whole subject of the Petises, thought it was a two-third grown one of the 

 common sort. The bird was skinned and cooked before my memory returned. 

 But the head, neck, legs, wings, many of the larger feathers, and a large part of 

 the skin, had been preserved. From these a very nearly perfect specimen has 



