Dissection of Sheep^s Brain. 167 



first two trunks proceed exclusively from the ganglion, and 

 are entirely sensory, viz. (a) the Ophthalmic, which enters the 

 Orbit and supplies the eyeball, the lachrymal gland, the 

 mucous lining of the eye and nose, and the integument and 

 muscles of the eyebrow and forehead : and (b) the Superior 

 Maxillary, which is continued forwards to the face below the 

 orbit, and supplies the side of nose, the lower eyelid, upper 

 lip, and upper teeth. The third or Inferior Maxillary trunk 

 receives a considerable part from the ganglion, and has asso- 

 ciated with it also the whole of the fibres of the motor root. 

 It therefore becomes a mixed nerve : and supplies the teeth 

 and gums of the lower jaw, the integument of the temple and 

 external ear, lower part of the face and lower lip, and the 

 muscles of mastication : it also supplies the tongue with its 

 special nerve of the sense of taste. 



The enlarged anterior part of the spinal cord immediately 

 succeeding the Pons is the Medulla Oblongata ; it rests its in- 

 ferior surface on the basilar groove of the occipital bone, and its 

 superior surface forms the floor of the fourth ventricle. Its 

 inferior surface, which we are now considering, is marked by 

 a median groove in which ran a small artery, a recurrent 

 branch of the conjoined Vertebral arteries : and, a little to the 

 right and left of this median groove, it is marked by a second 

 groove commencing at the Pons and bending outwards like a 

 hook : this marks the track of the Arciform Fibres, within the 

 bend of which is situated on either side an oval mass, termed 

 the Olivary Body ; and at the commencement of which, just 

 behind the Pons, is situated the Sixth Pair of Nerves : one 

 arising from each lateral half of the Medulla. 



The Sixth Nerve {abducem) is distributed to the ocular sur- 

 face of the External Rectus muscle of the eye. 



Between the Olivary Bodies and the median groove are the 

 * Anterior ' Pyramids. 



Between the Olivary body, and the Trifacial Nerve is the 



