274 ANIMAL INTBLLI6BN0E 



sides. If she did, and neglected to turn them every 

 day, they would assuredly be addled. Forasmuch as 

 she has not the faintest intention of revisiting the 

 eggs, they are contrived of a peculiar elongated shape, 

 like a soda-water bottle without the neck, and are set 

 on end in the material of the mound. The chicks are 

 hatched in due time, and are often so fully fledged on 

 escaping from the shell as to be able to take flight at 

 once, and are able to find without guidance the food 

 suitable for their needs. Hence there is no more pos- 

 sibility of the young birds acting upon instruction or 

 in imitation of their parents than there is in the case 

 of young spiders, seeing that the old birds evade the 

 labour of personal incubation and guidance of the 

 chicks. ' Yet,' says Mr. Savile-Kent, ' the mound-con- 

 structing instinct is so strongly ingrained by heredity 

 that young birds taken fresh from the nest and con- 

 fined under favourable conditions have at once com- 

 menced to construct mounds after the characteristic 

 manner of their tribe.' ^ In doing so, no doubt these 

 young and inexperienced creatures are acting under a 

 stimulus communicated from the lower brain centres 

 along the efferent nerves to legs and feet congenitally 

 developed and highly specialised for a peculiar func- 

 tion. So far the birds may be regarded as uncon- 

 sciously exercising innate proclivity, which, like other 

 idiosyncrasies, attains its highest activity at the season 

 of reproduction. When the adult megapode combines 

 for the first time with others of its species to construct 

 and stock the incubating mound, it is obeying the law 



^ The Naturalist in Australia, p. 33. 



