98 



ZOOLOGY. 



cerebellum, whilst in other animals (with scarcely an exception) 

 it does not. But the brain in all mammals is formed on precisely 

 the same ^)lan ; no parts have been left out. R. K.] 



7 9 10 11 6 e 



Fig. 65. Section of the Brain, Cerebellum, Pons, and Medulla 

 Oblongata.* 



* Vertical section of the cerebrum, cerebellum, pons Varolii, and medulla 

 oblongata ; a, anterior lobe of the brain ; b, middle lobe ; c, posterior lobe ; 

 d, cerebellum ; e, medulla spinalis ; f, section of the corpus callosum. The 

 lateral ventricles of the brain are situated on either side of the corpus callo- 

 sum, which assists in forming their upper wall, g, optic lobes : 1, olfactory 

 nerves ; 2, the eyeball, from which may be traced the optic nerve as far as the 

 optic thalami or lobes. Close to this is the nerve of the third pair. 4, the 



proceeding to the abducentes muscle ; 7, facial nerve; under the origin of 

 this nerve may be seen a portion of the acoustic ; 9, nerve called glosso- 

 pharyngeal ; 10, pneumogastric nerve ; close to it is, 12, the spinal acces- 

 sory ; these three nerves, the glosso-pharyngeal, pneumogastric, and spinal 

 accessory, are hy some reckoned as one pair ; 11, the ninth pair of some, 

 and the eleventh of others, called also hypoglossal ; 14 and 15, cervical nerves. 



