THE BRITISH NATURALIST. 



[August 



paper since all birds pass through one moult and some through two 

 before leaving the shell. Perhaps the word moult may mislead since 

 the first feathers are not cast but absorbed. These first feathers are 

 simple, barbless and of no use to the chick, and may not inprobably 

 be regarded as persistant representatives of the first leather-like 

 covering of their far off ancestors which has been referred to in the 

 earlier part of this paper. Some birds go through two moults within 

 the shell leaving it ready for flight, as do for instance, the megapodes^ 

 The most highly specialized of arian types are some of the flying 

 birds, and in them the young are hatched in a comparatively helpless 

 condition, depending for food upon their parents. In birds as m other 

 groups of animals the law holds good, " the more highly specialized 

 the adult, the more helpless the young." 



In the less highly organized birds the young are hatched in a less 

 defenceless condition, and in some we find this reversion to the reptilian 

 habit (for in all reptiles the young can take care of themselves as soon 

 as hatched} is very marked, as for instance the ostriches and casso- 

 w^aries, and more familiarly tlie lapwing and its allies, which though no 

 doubt more highly organized than the ostrich do not feed their young 

 but take them to their food. 



It may be noted also that those birds whose young when hatched 

 can fend for themselves, lay eggs relatively very large ; this is of course 

 due to the need of providing nutriment for the chick till it has attained 

 a somewhat advanced state of development. 



If there is one branch of natural history w^hich more than another 

 demonstrates the transmissability of both hereditary and acquired 

 characters it is oology, using the word not in its old narrow sense with 

 reference to the shape and colour of the shell, but in a higher and 

 broader sense as including not merely the hard outer covering but the 

 living organism within. An et^g liatched artifically will give rise to a 

 bird ; that bird though it has never seen either its parents or other 

 birds of its own species will feed true to its specific habits, i.e., if it 

 belong to a granivorous species it will take nought but grain, if to a 

 carnivorous species nothing but flesh. More than this, if male and 

 female birds artificially hatclied and which have never seen birds of 

 their own species, be paired, they will breed and build nests true to 

 ^he specific type. Why is this ? there is only one answer, i.e. hereditry. 

 In other words the experiences of countless generations have in- 



