BRAIN. 



133 



no pineal eye (parietal organ). The pituitary body lies along 

 the ventral side of the infundibulum ; it is said to open in the 

 adult into the cranial cavity within the dura mater (Haller), 

 but this must be regarded as doubtful. 



muscle of eye ; P sp nil nerved Prpalatoauadr^t'^'^^ ' °* '-^'"°'" ''"' 



internal, fls superior rectus m^cle of eve ^S«nirtU ,f°'!l',''' ""^^'^ = ^' external, Ri 

 ophthalmicus superficial trig^Sii- rr'luDerfor^TK'-tn'fiH^ nerve (trochlear) ; Tr' 



nerve ; V, tenth nerve (vag^.T^A ^^reS'KbraST'^TrSfal^^^^^^^^^^^ '""^ ^"'^ 



The cerebrum is generally marked by longitudinal grooves 

 mdicating the mternal division, but in Carcharias (Fig 78) 

 Sphyrna, etc., there are no traces of these. Plagiostomes 



