4 RETROGRESSIVE DEVELOPMENT IN NATURE. [IX. 



tives of the Mammalia in New Zealand. In former days it 

 would have been said that the Kiwi was created without wings, 

 because it had no need for them ; but now that we can no longer 

 hold the old simple doctrine of special creation, and are com- 

 pelled to believe that the animals and plants of every age have 

 not been suddenly created out of nothing, but have been de- 

 veloped from ancestral forms, such an assumption can have but 

 little weight. The idea of such special creation is not compatible 

 with the present state of our knowledge ; we cannot suppose 

 that the cause of all being called the forms of life into existence 

 in their present form by word alone, but rather by the action 

 of natural forces upon matter, these working together to pro- 

 duce the whole universe of everlasting change, seen in the 

 rise and decline of solar systems, no less than in the evolution 

 and extinction of species. We do not hold that the Kiwi 

 was created out of nothing, but that it was developed from 

 older forms, from species of birds very unlike itself. These 

 birds again were evolved from lizard-like reptiles, which pos- 

 sessed fore- as well as hind-limbs : hence the primitive birds 

 must have had these also, and their fore-legs must have been 

 gradually changed into wings. It is, therefore, certain that 

 the ancestors of the Kiwi possessed wings. Why, then, should 

 the Kiwi have lost them ? 



Furthermore we have positive evidence in support of the 

 above conclusion that the ancestral form possessed wings, 

 which have been eliminated in the existing species — because 

 the Kiwi even now bears traces of them as minute rudiments 

 hidden under its feathers, and although these no longer serve 

 any purpose, the essential structure of the wing is plainl}^ 

 recognizable, and there are even some short crooked feathers 

 which, with their strong shafts, are very like true primary 

 quills. 



The actual reason why the Kiwi possesses only rudimentary 

 wings is, of course, to be found in the fact that, with its present 

 structure and habits, they would be useless to it, and so far we 

 should be justified in saying that the bird has no wings because 

 it has no use for them. The Kiwi is certainly formed for 

 terrestrial life ; its short but strong legs and feet are adapted 

 for scratching the earth or digging out holes under the roots of 

 great trees, and enable it to make its escape swiftly and noise- 



