XIII 



PHYLUM CHORDATA 



147 



the optic thcdami. Attached to the roof is a slender tube, 

 the epiphysis cerebri or pineal body (Gp.\ which runs forwards and 



^1 



Iff 

 II VL1ISH 



mix x 



vw 



Fia. 775. Brain of Scylliutn canicula. A, dorsal view; B, ventral view; C, lateral view. 

 F. rho. fossa rhomboidalis (fourth ventricle) ; Gp, epiphysis ; HH, cerebellum ; HS. A , hypo- 

 physis ; L. ol. olfactory lobe ; MH, mid -brain ; NH, medulla oblongata ; Sv, saccus vasculosus ; 

 Tro, olfactory peduncle ; UL, lobi inferiores ; VH, prosencephalon ; ZH, diencephalon ; 

 //, optic nerves ; ///, oculomotor ; IV, pathetic ; V, trigeminal ; VI, abducent ; VII, facial ; 

 VIII. auditory ; IX, glossopharyngeal ; X, vagus. (From Wiedersheim.) 

 1 



terminates in a slightly dilated extremity fixed to the membranous 

 part of 'the roof of the skull. Projecting downwards from its 



L 2 



