^: --^Prechordal ^ 



'"-■^ — ^ -Optic capsule 



Olfactory capsule 



Lens 

 ■Retina 



Otic capsule 



Synotic tectum' 

 Notochord- 



A. Chondrocranial 

 Cartilages 



B. Early Chondrocranium 



Fig. 61. Development of the Chondrocranium. In (A) the cartilages are 



shown lying on either side of the notochord, and surrounding the organs 



of special sense; (B) shows the fusion of the cartilages to form the 



primitive chondrocranial trough. 



Brain 



Parachordal 



Otic 

 cap^ide 



Notochord 



Fig. 62. Cro.ss section of (A), Fig. 

 61, through the otic region. 



Otic capstde 



Foramen magnum 



Fig. 63. Posterior View of (B), 

 Fig. 61. The narrow synotic tec- 

 tum is the only roof of the chon- 

 drocranium in the higher verte- 

 brates. 



