838 



THE NERVOUS SYSTEM OF THE OX 



11. Short and variable fissures occur in front of and behind the middle branch of the lateral 

 fissure (F. ectosylvia anterior, posterior). 



The olfactory bulb is much smaller than in the horse. The lateral olfactory 

 stria is large, the medial one small and not distinct. 



The cranial nerves have in general the same superficial origin as in the horse. 

 The more important differences in other respects are as follows: 



The oculomotor nerve is larger than in the horse. It emerges with the fourth, 

 sixth, ophthalmic and maxillary nerves through the foramen orbito-rotundum. 



The trigeminal nerve presents the following differences in its distribution: 



Cercbennm 



Optic -nerve 

 Tnfimdihulum 

 Hypophysis 



Olfactory 

 bulb 



Medulla 

 oblongata 



Pons Cerebral 

 peduncle 



Fig. 665. — Sagittal Section of Brain of Ox. 

 V.IV. Fourth ventricle; P.c, choroid plexuses: T'.m., anterior medullary velum; A.c, cerebral aqueduct; C.q., 

 corpora quadrigemina; C.p., posterior commissure; Cpin., pineal body; V.c.i., great cerebral vein; T, thalamus; 

 F.J/J., third ventricle (arrow points to interventricular foramen) ; C.a., anterior commissure; L.(., lamina terminalis; 

 Co., chiasma opticum. Fissures: i, callosal; .S, calloso-marginal; S, aplenial; 4. transverse; 5, entomarginal. 



The internal branch of the lacrimal nerve supplies twigs to the mucous mem- 

 brane of the frontal sinus; the large outer branch runs backward and supplies the 

 corium of the horn. The frontal nerve emerges from the orbit below the supraor- 

 bital process. The naso-ciliary nerve is large and sends filaments to the ocular 

 muscles. The ciliary ganglion is somewhat larger than in the horse, and is con- 

 nected with the lower division of the oculomotor nerve by several short filaments. 

 In consequence of the absence of the canine and upper incisor teeth the correspond- 

 ing branch of the infraorbital nerve is naturally wanting. The mandibular nerve 

 emerges through the foramen ovale. The superficial temporal nerve gives off a 

 large branch which joins the superior buccal division of the facial on the masseter, 

 about half-way between the zygomatic arch and the angle of the jaw. The otic 

 ganglion is larger than in the horse. According to Moussu the buccinator nerve 

 furnishes excito-secretory twigs to the parotid and inferior buccal glands. 



