DEVELOPMENT OF EMBRYO OF FOWL. 



43 



being very small, and evidently partially destroyed by the opera- 

 tion. As the first leg-somite is the seventh post-brachial, the 

 absence of rudiments of the hind limbs in this embryo is readily 

 understood. 



B 



FIG. 5. Three sections from a sagittal series through the embryo shown in Fig. 4. 

 A, amnion ; Ao., aorta ; B.C., ganglia of the nerves of the wing ; B.P., nerves of 

 wing; C, cord; N, notochord ; V. U., umbilical vein ; IV.)., Wolffian duct; 1-5, 

 first to fifth postbrachial ganglia or nerves. 



Thus there are two somites less in this embryo than in that of 

 experiment 125. In the latter, which includes one leg somite, 

 rudiments of the hind limbs are formed ; in the present case no 



