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THE BRITISH NATURALIST. 



91 



fused as in the adult bird. Having seen how a feathered arboreal 

 reptile had arisen from the original scaly ancestor, it is not difficult to 

 undertand that the more active ones, hopping about after their insect 

 prey or gliding with outspread limbs from tree to tree, would vary in 

 different directions ; those which continued to go on all fours would 

 not have the hands and feet feathered ; the mere fact of using all four 

 limbs for progression would prevent the growth of feathers on their 

 under surfaces ; any tendency to an erect posture would mean that 

 though there would be no feathers on the under surfaces of the hind 

 limbs, those on the fore limbs would be well developed. It may be 

 said that if there was as we have assumed a development of scales 

 into feathers this should take place all over the body, to this we must 

 reply that as in mammals the palms of the hands and the soles of the 

 feet are devoid of hair, we may justly assume that in feathered animals, 

 parts similar both in structure and function would be devoid of 

 feathers. Any tendency to an erect attitude accompanied by disuse 

 of the fore-limbs, as organs of progression or prehension, would mean 

 the growth on them, as on other parts of the body, of feathers; and as 

 the animal hopped about, or sprang from bough to bough, using its out- 

 stretched fore-limbs as balancers, any variation in the direction of 

 greater length of the feathers of the fore-limb would be advantageous 

 and would tend to be preserved and accentuated. It must be noted, 

 in support of the erect posture and hopping theory, that no bird 

 commences to fly without first springing upwards, this applies even to 

 sea-birds, and we all know that swifts cannot rise from the ground 

 except against a strong wind, and even then only with difficulty. 



The well developed feathered fore-limbs which were most effective 

 as balancers, could be used as organs of flight, and since there is 

 reason to believe that at first flight was irregular and spasmodic, we 

 need not doubt that as increased structural modifications and increased 

 functional activity had so far marked the development of reptiles in 

 an ornithic direction, so those individuals which possessed the 

 power of even irregular flight in a somewhat greater measure than 

 their contemporaries, would be able to get a greater variety and 

 quantity of food as well as possessing an advantage in securing the most 

 vigorous females, and thus in these various ways tending to preserve and 

 accentuate their ornithic development. Arguing by analogy we may 

 say, paradoxical though it sound, that the first bird was a male, for just 



