ii Journal of Comparative Neurology. 



(i) Supra-orbital canal (superficial ophthalmic, cross hatched — 

 the black segment is the portion innervated by the profundus) = cran- 

 ial (C) + rostral {R) -f sub- rostral {SR). 



(2) Infra-orbital canal (buccal + otic, dotted) = orbital OR + sub- 

 orbital {SO) -f portion of angular (A) -f nasal (N). 



(3) Hyomandibular or Operculo-mandibular canal (external man- 

 dibular, black) = remainder of angular {A) + oral {O) + jugular (/). 



(4) Lateralis canal (lateralis, oblique shading) := lateral (Z) + occip- 

 ital {Oc) + aural {Au) + post-aural {FAu). 



Nothing new is described with respect to the olfactory and optic 

 nerves. 



The the third nerve after giving off a branch to the superior rectus 

 divides into superior and inferior branches, the former proceeding 

 dorsal to the optic and also the inferior rectus and inferior oblique to 

 the internal rectus which it innervates. The ventral branch near its 

 origin gives off a fine radix brevis which is joined by a radix longa 

 from the ophthalmicus profundus At their junction lies the ciliary 

 ganglion which gives off two ciliary nerves. This ganglion thus does 

 not correspond to the group of ganglion cells on the ventral branch of 

 the III and described by Schwalbe as the ciliary — probably both are 

 present. 



The profundus also gives off some ciliary nerves. 



The Pathetictts has a typical exit and course. It proceeds under 

 cover of the superficial ophthalmic for a portion of its course to the 

 superior oblique. 



The Abducens arises by six rootlets at a level slightly behind the 

 dorsal root of the Vllth and a little in front of the root of the glosso- 

 pharyngeal. It runs under the Vth and Vllth, closely applied to the 

 former and enters the orbit by a foramen hidden by the Vth and Vllth 

 trunk. It, of course, innervates the external rectus. 



The Trigeminus is entirely distinct from the facial, arising by two 

 closely applied roots from the side of the medulla. Whether the ante- 

 rior smaller root is the root of the profundus could not be anatomically 

 shown by dissection. As the V enters the orbit, it gives off a fairly 

 large bundle to the VII. This bundle divides, one part accompanying 

 the inner buccal, not further traceable, and the larger part accompany- 

 ing the outer buccal, a portion separating again from the latter. This 

 is stated to constitute " the ottly confusion or mingling between the 

 facial and trigeminal nerves in Chimaera." The principal branches of 

 the Trigeminus are the Profundus (P), the Superficial Ophthalmic 



