The Eggs of Birds 433 



in the young of many, if not all, other Phyla of animals, 

 and which is one of the most interesting provisions brought 

 about by the slow but sure working of evolution. We 

 may instance the few eggs of the voracious and masterful 

 sharks and the millions of spawn necessary to enable 

 the halibut and the cod to continue in existence. 



Mr. Ernest Ingersoll has so admirably summed up 

 the matter of this relation of the number of eggs to the 

 corresponding danger that I cannot do better than to 

 follow his argument, quoting his words with a slight 

 change here and there. This phase of the study of eggs 

 being so clearly understood, it is well worth a little detail 

 as an illustration of how interesting all the other problems 

 will become when we once get on the right road to their 

 solution. 



Among the majority of birds the average number of 

 eggs in a nest is from three to six; we may take five as a 

 typical average. "Any considerable departure from this 

 normal number in a species or Family must then be ac- 

 counted for by some specific or tribal peculiarity in cir- 

 cumstances. 



" Beginning with the ostrichlike group at the bottom 

 of the list, we find ourselves face to face with an inter- 

 esting state of things, to which the number of eggs is 

 an index. Ostriches, rheas, and emeus incubate large 

 clutches a dozen or more, those inhabiting the conti- 

 nents of Africa and South America, however, producing 

 twice as many eggs annually as their relatives of Australia 

 and the neighbouring smaller islands. 



" Immediately following and contrasting with them are 



