Stowell.] 462 [May 21, 



origin demonstrated by Meynert (28, p. 732 et seq.) and by Spitzka (26, 

 The Central Tubular Grey, p. 72).? 



Ex. dorsalis is apposed to the medipeduncle, and is traceable with it into 

 the cerebellum. 



Ex. candalis extends parallel with the meson to a region of the meten- 

 cephal just entad of the olive. 



This considerable fascicle points to an ental origin several mm. caudad 

 of a transection through the caudal border of the pons, and in the region 

 of the olive. 



Ex. centralis : The fourth radicule comes from the epiccele in the same 

 region as the ventral root of Rx. motoria ; its course is laterad, and lies 

 caudad of the medipeduncle, and ventrad of the medipeduncle and pre- 

 peduncle. 



Ectal Origin: There is some variation in the ectal origins of this nerve 

 in different animals. This variation may be referred to the variation in 

 general configuration of the brain, and does not prevent homologization. 



" When the pons is less developed than in man, the nerve (trigeminus) 

 is attached behind (caudad of) that part between it and the trapezium of 

 the medulla oblongata" (30, Vol. ii, 270). 



Wilder summarizes as follows : "In the cat the nerve is always nearer 

 the caudal than the cephalic border of the pons." "Sometimes the entire 

 nerve passes just caudad of the pons, which is then usually somewhat 

 emarginate at that point." "Sometimes, perhaps more often, some of the 

 fibres of the nerve interdigitate with those which form the caudal margin 

 of the pons" (33). 



As already indicated, the proximate roots by their confluence form two 

 nerves with distinct ectal origins, but which are intimately related in their 

 distribution. 



Eadix motoria (Rx. mtr.), the smaller of these nerves, lies upon the 

 mesal border of Rx. sensoria. It is a slender ribbon-like packet composed 

 of 6-9 funiculi ; it sustains this general relation for about 5 mm.; near the 

 cephalic border of the pons it crosses the ventral surface of a large flat- 

 tened ganglion, G. gasseri, q. v., and finds its exit with N. mandibularis 

 through the oval foramen. Its distribution is given with N. mandibularis. 



Eadix sensoria (Rx. sn.), the larger and ganglionic nerve, takes its ectal 

 origin from the proximate roots which lie chiefly caudad of the pons. The 

 caudal border of the nerve is not infrequently in a line with the caudal 

 border of the pons, but this relation is occasioned by the emarginate bor- 

 der of the pons against which the nerve-trunk rests. 



• In the examination of the brains of Felis leo and F. conrolor (one of 

 each) and F. dome&lica (a large number), in the museum of Cornell Uni- 

 versity, I have not found a single instance in which any fibre of the pons 

 passes wholly caudad of the trigeminus. Only a lew of the fibres of the 

 cephalic border of Rx. sensoria ever interdigitate with the pons, and this 

 condition does not exist in the majority of brains examined. In some of 

 the brains hardened in alcohol a few filaments from the pons seem to be 



