130 MAMMALIA. 



ganglion near the first trunk of the fifth, at the part receiving the branches from the 



x 



superior cervical ganglion of the sympathetic ; it appears to be a continuation of one 

 of those branches of the sympathetic which also communicated with the sixth ; it 

 passes into the orbit, and receives a branch from the third nerve to form the ciliary 

 ganglion. In the sheep and goat, the branch given to the lenticular ganglion arises 

 from the Gasserian ; in the goat it is a very slender thread, but divides into two, one 

 of which joins the lenticular ganglion, the other, one of the ciliary nerves arising from 

 this. In the dog, the branch joining that of the third nerve in the lenticular ganglion 

 proceeds from the superior nasal. 



The fourth nerve, as in man, arises behind the quadrigerninal bodies from the 

 oblique tract, descending near the roof of the passage from the third to the fourth 

 ventricle. It terminates on the superior oblique muscle of the eye. 



The larger portion of the fifth emerges from the crus of the cerebellum and the 

 annular tubercle ; one portion of it arises from the involuntary centre, the other from 

 the sensitive centre forming the ventricular cord on the floor of the fourth ventricle ; 

 the smaller portion is on the inner side, and arises from the tract of the larger portion 

 of the intermediate layer of the external region. With the exception of those of the 

 smaller portion, its fibrils undergo a change of arrangement in the Gasseriau ganglion, 

 and become formed into three trunks, the smaller portion passing with the third. In 

 many animals, as the horse, ass, calf, and goat, the fibrils forming its trunks, and 

 particularly the second, are very coarse ; but not in others, as the dog, baboon, and 

 monkey. It appears to communicate with the sympathetic, particularly at the 

 Gasserian ganglion. In the porpoise the fifth has a larger and smaller portion. The 

 smaller is placed on the posterior and median margin of the larger as they emerge 

 from the annular tubercle : the larger forms a Gasserian ganglion, but the smaller 

 portion continues separate. 



The first trunk differs very little from that in man. In the calf the branch of the 

 superior nasal passes through a foramen to the superior part of the cribriform plate, 

 but continues to be covered by the dura mater lining this, to which it gives filaments ; 

 two principal branches enter the nose, one passes on the Schneiderian membrane of 



