FIG. 515. TRANSECTION OF THE SPINAL CORD OF AN EMBRYO CHICK. 



c. rod. ant., axons to the ventral roots; c. rod. post., axons to the dorsal roots; 

 col, collateral from an axon back to the gray matter; gg, dorsal root ganglion; roc. 

 ant., ventral root; roc. post., dorsal root. (After van Gehuchten.) 



Head/a 



Neuropore 



Anterior cerebral 



I vesicle, or pros- 



encephalon 



Pharynx - 



Vitellin iein~ 



Middle cerebral 



vesicle, or mes- 

 encephalon 



Posterior cerebral 



vesicle, or rhomb- 

 encephalon 



FIG. 516. RECONSTRUCTION OF THE ANTERIOR PORTION OF THE BODY OF A YOUN 

 CHICK EMHKYO, SKKN HIOM THE DORSAL SURFACE. (After Kollmann.) 



