362 Mr. W. P. Pycraft on the 



locomotion quite probable, and may therefore be said to 

 entirely corroborate Mr. Quelch's statements. The hand is 

 considerably longer than the forearm, the poUex or thumb 

 extends beyond the level of the tip of the 3rd digit, and is 

 provided with a large claw ; the 2nd digit, with an equally 

 large claw, is produced beyond the fold of skin running along 

 the posterior border of the wing, which encloses the base 

 of the quills. Of these, it will be noticed, only 1-8 have 

 extended any distance beyond the wing-fold just mentioned, 

 so that a long free finger-tip is left. As the bird grows and 

 the feathers develop, the proximal ones grow faster than the 

 distal, so as not to impede the freedom of the hand in climb- 

 ing ; but as soon as the proximal feathers have increased suffi- 

 ciently to serve to break the force of a fall, should such occur, 

 the remaining distal feathers begin to develop ; at the same 

 time the hand begins to shorten till, as will be seen in fig. 4, 

 p. 361, in the adult, the hand has become shorter than 

 the forearm, the claws have disappeared, the thumb no longer 

 extends to the level of the 3rd digit, nor does the 2nd project 

 beyond the posterior wing-fold, the bird now being able to move 

 from one place to another by flight instead of by climbing.^' 



Should a nestling by any chance fall into the water, it 

 seems that it is able to save itself by swimming, since 

 Mr. Quelch tells us that on one occasion, happening to drop 

 a youngster from a boat into the river, it immediately dived 

 out of reach ; coming to the surface a yard or so further on, 

 it again dived, and finally escaped by gaining the shore and 

 disappearing among the herbage. 



It is not improbable that the life-history of Op'isthocomus is 

 a survival of what was at one time shared by the Galli, since 

 in nestlings of Cracidde and Gallida the wing exhibits 

 precisely the same phenomena as we have just noticed in 

 Opisthocomus ; the details, however, are not quite the same, 

 inasmuch as in Opisthocomus we have an order of things at 

 their maximum development, whilst in the Gallidce and 

 Cracidce we have the same order in its decline, and responding 

 to the demands of a changed environment. 



In the wing of the nestling of Crax, the Common Fowl 



