ON THE LIMBS OF THE CHICK. 



shown in Fig. 2, A, G. In Fig. 2, B, the left side is indicated. 

 Sections of this chick show concentrated areas where the skeleton 

 is beginning to develop. These areas are indicated in Fig. 3, 

 A, B, C, and D by dots. A section of the normal side of the 

 embryo is given in Fig. 3, D. 



I have not succeeded in keeping any embryos alive beyond 

 the ninth day of incubation, but a normal embryo of this age 

 possesses w r ings and legs which are readily distinguishable. My 



B 



D 



FIG. 3, A and B. Sections of the grafted wing W showing rudiments of the 

 skeleton R; C, section of the leg L with the rudiments of the skeleton R; D, 

 section of the left side. The leg L appears in cross section, the wing W in longi- 

 tudinal section. 



results show that the operation greatly retards the development. 

 If the embryos could be kept alive a few days longer it would, 

 no doubt, be possible to determine positively whether or not 

 the grafted tips become a part of the limb to which they are 

 attached irrespective of their former position. The results of 

 my experiments indicate that they do. The failure to keep the 

 embryos alive is probably due to disturbance of the development 

 of the allantois. 



In regard to regeneration the results obtained from the removal 



