36 



crossing the Santa Cruz river, where it* course was about 400 yards 

 wide and the stream rapid. They make but slow progress, their necks 

 are extended slightly forwards, but little of the body appears above 

 water. At Bahia Blanca, in the months of October and September, 

 an extraordinary number of eggs are found all over the country. 

 The eggs either lie scattered about, or are collected together in a 

 shallow excavation or nest ; in the former case they are never hatched, 

 and are termed by the Spaniards Huachos. The Gauchos unani- 

 mously affirm that the male bird alone hatches the eggs, and for 

 some time afterwards accompanies the young. Mr. Darwin does 

 not doubt the accuracy of this fact, and states that the cock bird 

 sits so closely that he has almost ridden over one in the nest. Mr. 

 Darwin has also been positively informed that several females lay in 

 one nest, and although the fact at first appears strange, he considers 

 the cause sufficiently obvious, for as the number of eggs varies from 

 20 to 50, and, according to Azara, even 70 or 80, if each hen were 

 obliged to hatch her own before the last was laid, the first probably 

 would have been addled ; but if each laid a few eggs at successive 

 periods in different nests, and several hens, as is stated to be the 

 case, combine together, then the eggs in one collection would be 

 nearly of the same age. Mr. Burchell mentions that in Africa two 

 ostriches are believed to lay in one nest. 



Mr. Darwin then proceeds to notice the other species of Rhea, 

 which he first heard described by the Gauchos, at River Negro, in 

 Northern Patagonia, as a very rare bird, under the name of Avestruz 

 Petise. The eggs were smaller than those of the common Rhea, of 

 more elongated form, and with a tinge of pale blue. This species is 

 tolerably abundant about a degree and a half south of the Rio Negro, 

 and the specimen presented to the Society was shot by Mr. Martens 

 at Port Desire in Patagonia, (in latitude 48). It does not expand 

 its wings when running at full speed, and Mr. Darwin learned from 

 a Patagonian Indian that the nest contains fifteen eggs, which are 

 deposited by more than one female. It is stated in conclusion that 

 the Rhea Americana inhabits the country of La Plata as far as a little 

 south of the Rio Negro, in lat. 41°, and that the Petise takes its place 

 in Southern Patagonia. 



Mr. Chambers then brought before the notice of the Society a 

 simple process for taking impressions from feathers, which is effected 

 by placing the feathers between two sheets of paper, the lower one 

 being previously well damped, and the upper covered with printers' 

 ink; both are then passed through the rolling press of a copper plate 

 printer, and on removing the upper sheet perfect figures of the fea- 

 thers will be left, which may be coloured when dry, and will then 

 have the resemblance of feathers placed on paper. 



