206 



COMPARATIVE ANATOMY 



- L.ol. 



NH IV Z.ff 

 lilt Mil 



' 



-Lot 



B 



IT/ r/ 



L.ol 



FIG. 154. BRAIN OF LARVAL LAMPREY. A, from above ; B, from below; 



C, from the side. 



, ganglion habenulae ; Op, pineal organ ; HH, cerebellum ; Hyp, hypophysis ; 

 L.ol, olfactory lobe ; ^f^<l, spinal cord; MH, mid-brain; NH, medulla 

 oblongata ; S l , S', first and second spinal nerves ; &v, saccus vasculoslis ; 

 VH (Jias.Gf), cerebral hemispheres between which, in A, the median portion 

 of the telencephalon is seen, with the pallium removed ; ZH ', diencephalon ; 

 I-X, cerebral nerves. 



blindly in it anteriorly. The cerebellum is relatively much larger 

 than in the Lamprey, and projects posteriorly so as to cover the 

 fourth ventricle completely : it resembles that in certain embryonic 



