COORDINATION IN ANIMALS 



187 



The three- vesicle brain now becomes transformed into one 

 of five vesicles by a hollow outpocketing from the anterior end 



FIG. 104. Diagrams to illustrate the general method of transformation of the 

 anterior end of the neural tube into the brain. A, B, C, median vertical sec- 

 tions; D, dorsal view of C. a, fore-brain; b, mid-brain; c, hind-brain; d, prosen- 

 cephalon; e, diencephalon; /, cerebellum; g, medulla oblongata; h, cerebral hemi- 

 spheres; i, olfactory lobes; j, pineal body; k, inf undibulum. 



of the fore-brain and a dorsal outpocketing of the hind-brain. 

 In some of the lower Vertebrates the brain throughout life 



