vi HABITS OF THE OSTRICH 281 



until the nest is full, which is the case when it contains 

 thirty eggs, but even afterwards. These last -laid eggs lie 

 irregularly round about the nest, and seem to be intended by 

 nature to satisfy the rapacity of the enemies above mentioned, 

 to whom she prefers to surrender these fresh eggs than those 

 already incubated. But these eggs have also a more im- 

 portant use, namely, to serve as the first food for the young 

 ostriches, which when they are hatched are as big as an 

 ordinary fowl, and whose tender stomachs are not at first able 

 to digest the hard food of the adults. The old ones them- 

 selves break these eggs for them one after another, and in a 

 short time with this nutritious food bring them on so far that 

 they are able to seek their own food." The same observation 

 has also been made by others, and Brehm doubts it on in- 

 sufficient grounds. 1 That there are cases of young animals 

 fed by the parents' eggs is proved by the black Alpine sala- 

 mander (Salamandra atra). This animal brings forth living 

 young without gills and with completely developed lungs, in 

 complete contrast to all other tailed Amphibia, the young of 

 which are born with gills, and this is well known to be due 

 to the fact that the conditions of life of the Alpine sala- 

 mander do not allow it to deposit its eggs in the water. The 

 young, therefore, under the stress of the external conditions, 

 develop, until the lungs are completely formed, in the oviducts 

 of the mother. In these oviducts a remarkable struggle for 

 existence takes place, so that only one larva develops in each, 

 and this nourishes itself at the expense of the other eggs in 

 the oviduct until it reaches its maturity. I mention this 

 because Brehm regards it as something entirely novel that 

 birds should be fed on their parents' eggs. Such a method 

 of nutrition occurs only in this single instance among 

 Amphibia. 



Thus in the Alpine salamander most of the eggs which 



1 Loc. cit. voL vi. pp. 198, 199. 



