HEUISECTION OF THE HEAD. 



305 



Preparation— Fig. 88— See p. 303, exposure and dissection- 

 Fig. 88. 



Explanation of Fig. 88. — Atlas, az. — The first cervical vertebra. 



Axis, az. — The second cervical vertebra ; its odontoid process (Fig. 53) is sliown pro- 

 jecting cephalad into tlie ring of the atlas. 



Callosum, Corpus callosum, as. — The great commissure of the hemispheres. (For this 

 and the other parts of the brain, see Kg. 117.) 



'''.1 





Fig. 88.— Hemibection op the Head; xl. Compare with Pig. 59 and 117 and with 



Plate II, Fig. 4. 



Cn. (Canalis) Eustachiana.— The canal connecting the middle ear or tympanum with 

 the pharynx. Its crescentic opening into the pharynx is shown in this figure. 



Cn. (Canalis) neuralis, az.— Neural or vertebral canal.— The neural canal is repre- 

 sented by the deeply shaded space in the vertebrae in which the myelon rests. (The name 

 is put upon the muscles dorsad of the roof of the arch of the atlas and axis. Through 

 an inadvertence no dotted line is drawn from it to the canal ) 

 30 



