66 PROVIDENTIAL ADAPTATIONS [CHAP. n. 



in which they are always placed, i. e., vertically, with the 

 smaller end downwards ; the egg being compressed in 

 every part as nearly as possible towards the axis, in 

 which the centre of gravity lies, there is the least pos- 

 sible tendency to its equilibrium being destroyed when it 

 is placed in vertical position. A second peculiarity is the 

 extreme thinness of the shell, and its consequent fra- 

 gility. This is so great, that, unless the egg is handled 

 with the greatest care, it is sure to be broken, and 

 every effort which has been made to hatch these eggs 

 under domestic fowls has failed, the egg having in every 

 instance been broken by the bird under which it was 

 placed."* 



What need of a firm shell for an egg which has not 

 to bear a touch, from the moment of laying to that of 

 hatching, but which is intended to remain an undis- 

 turbed deposit in a hot-bed, till the marvellous work of 

 transmutation into a living creature shall have been 

 completed ? The substance of the shell was not wanted, 

 and is not supplied ; the form, by which it rests se- 

 curely in its place, has been provided for. And the 

 Chicks, which have to effect their own deliverance from 

 this cumbrous nursing cradle, are not like the flabby 

 nestlings that are hatched on the branching twig, or in 

 the snug thicket : " the young emerge fully feathered, 

 and capable of sustaining life by their own unaided 

 efforts, The young one scratches its way out alone ; 

 the mother does not assist it. They usually come out 

 one at a time ; occasionally a pair appear together. The 

 mother, who is feeding in the scrub in the vicinity, 

 hears its call and runs to it. She then takes care of 



* Gould's Introduction to the Birds of Australia, p. 85. 



