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next the ungual phalanx, and then the other phalanges in regular 

 succession from the distal to the proximal. 



Dissections show that the first phalanx of the third digit is always 

 well developed, but the second is usually represented only by a small 

 vestige which is pointed at its distal end and fused with the first 

 phalanx at the other (Fig. 6). In birds with the finger projecting 



Fig. 6. Varying stages in the development of the second phalanx of the third digit. In 

 the upper figure the phalanx is a mere knob, fused to the end of the first phalanx ; 

 in the middle figure it is longer, but still fused ; while in the lower it is a distinct free 

 bone, knobbed at its distal end, in correlation with the callosity on the skin (cf. 

 PI. V, fig. 2). I, II, III, first, second and third digits. 



