180 



THE SPINY DOGFISH— THE SKATE 

 o.l. 



...IT 



Fig. 62. — Ventral View of the Brain of the 

 Dogfish {Acanthias). After Purser. With 

 permission from J. Graham Kerr's Zoology 

 for Medical Students. 



0,1., olfactory bulb; i.l., inferior lobe; pt*., pituitary 

 body ; II-X, Roots of Cranial Nerves. 



2. The Cranial Nerves. 



The following is a list of the cranial nerves and their chief branches : — 

 I. Olfactory. 



II. Optic. 



III. Oculomotor. 



rV. Pathetic. 



V. Trigeminal 



VII. Facial 



VIII 

 IX 



(a) Superior ophthalmic. 



(b) Inferior ophthalmic. 



(c) Maxillary. 



(d) Mandibular. 

 VI. Abducent. 



(a) Superior ophthalmic. 



(b) Buccal. 



(c) Palatine. 



(d) Hyomandibular. 

 Auditory. 

 Glosso-pharyngeal. 



({a) Branchial. 



X. Vagus < (b) Visceral. 

 [(c) Lateral. 



In dissecting out the cranial nerves and the eye muscles it is best to do so in 

 the following order : — 



(i) The olfactory nerve (I), represented by a nimiber of fine branches 

 arising from the anterior end of each olfactory lobe and passing at 

 once into the olfactory capsule, where they become distributed to the 

 epithelium of the olfactory organ. 



(ii) The pathetic nerve (IV), arising from the dorsal surface of the brain, be- 

 tween the anterior part of the cerebellum and optic lobes, and passing 



