146 



Basic Structure of Vertebrates 



Nervus terminate 



Olfactory tract 



Nasal capsule. 



Olfactory bulb 



/ Olfactory nerve N. I 

 / Rhinoccele 



Lateral ventricle 



Cerebral hemisphere 

 , Interventricula 



Epiphysis 



(^£\ Optic nerve N. II 



Jl&S- Thalan 



Optic lob, 



jB. Trochlear nerve N. IV 



L 



phalon 



h- 



,^^S -- Acoustic nerve N. VIII 



— j* Tuberculum acuslicum 



Cerebellum 



Lobus lineae lateralii 



----Facial nerve N. VII 



Medulla oblongata --- 



Glossopharyngeal nerve N. IX 

 Medial longitudinal fasc. 



Visceral lob 

 Vagus nerve N. X 



Spinal cord 



—^ \tourth ventrich 



lv {Metencephalon 



(Fourth ventricle 

 Myelencephalon 



Fig. 136. (Left) The brain of the dogfish, Squalus acanthias, dorsal view. 

 (Right) The brain of the dogfish, Squalus acanthias, with the ventricles opened, 

 dorsal view. (Courtesy, Ranson: "The Anatomy of the Nervous System," Phila- 

 delphia, W. B. Saunders Co.) 



Cerebral hemisphere 



Optic lobe 

 Paraphysis I i . ■. Metacazlt 



Olfactory tract 

 Olfactory bulb 



Tuberculum acusticum 

 Tela chorioidea 



I Fourth ventricle 

 Visceral lobe 



-Y \ i 5 ""T"' 



Telencephalon I i I ] j \ Metencephalon Myelenccphalo 



Preoptic recess - , ; MesencepMon 



Vemm transversnm , j Saccus vasculosis 



Optic chiasma Third ventricle 



Fig. 137. The brain of the dogfish, Squalus acanthias, sagittal section. (Cour- 

 tesy, Ranson: "The Anatomy of the Nervous System," Philadelphia, W. B. 

 Saunders Co.) 



