198 



ZOOLOGY 



SECT. 



is rounded and placed at the end of a hollow stalk : a shorter 

 offshoot of the roof of the diencephalon may perhaps represent^ 

 a rudimentary pineal eye. Behind the pituitary body is a saccus- 



L.o'l 



B 



YJT 



~\m 



L.ol. if?* 



FIG. 818. Salmo fario. Dorsal (A), ventral (B), and lateral (C) views of brain. EG, or ax G. 

 corpora striata ; '/,, crossing of optic nerves ; G. j>, pineal body; HH. cerebellum; Jf>/j>. 

 pituitary body ; I, if. infunclibulum ; L. ol. olfactory lobes ; M, <i, spinal cord ; MH, optic lobes ; 

 SI!, medulla oblongata ; Pull, pallium ; Sv. sai-cus vasculosus ; 7',-. <> t >t. optic tracts ; U, L, 

 lobi inferiores ; VII, prosencephalon ; 7 A", cerebral nerves ; XII. 1. tirst spinal (hypoglossal). 

 nerve ; 2, second spinal nerve. (From Wiedersheim's /" ,-t<i>,-<tt<t.) 



vasculosus (s. v.). The optic nerves do not form a chiasma, but simply 

 cross one another or decussate (Ch.) on leaving the brain, the 

 right nerve going to the left, and the left nerve to the right eye. 



