216 D. DAVIDSON BLACK 



Cranial nerves. As has already been mentioned in the gross 

 description, the olfactory bulbs and tracts are entirely wanting. 



The optic nerve is represented by a few fibrous strands which 

 pass from the bulbus oculi at the region of entrance of the central 

 artery into the surrounding connective tissue of the orbit. As 

 no microscopic examination was made of these, it is impossible to 

 say whether any true nerve fibers were present. No connection 

 existed between the eye and the central nervous system. 



The deep connections of the cranial nerves from the oculomotor 

 caudad are practically normal and will be but briefly noted here. 



The oculomotor nerve (N.III, figs. 36 to 39) is essentially nor- 

 mal in its origin. Cephalad, the oculomotor nuclei {Nu.N.III) 

 are in relation with a well marked nucleus of the posterior longi- 

 tudinal bundle or nucleus of Darkschewitsch (Nu.f.l.m.). Some 

 of the more caudal fibers of this nerve have a crossed relation. 

 The emergent fascicles do not pierce the red nucleus but curve 

 around its caudal and mesial surfaces. 



The trochlear nerve (N.IV. figs. 32 to 35), although very 

 small, can be made out readily. Its nucleus {Nu.N.IV) is in rela- 

 tion to the posterior longitudinal bundle and its root fibers pass 

 towards the superior medullary velum on the median aspect of 

 the mesencephalic root of the trigeminal nerve. The decussa- 

 tion in the velum is quite normal. 



The trigeminal ner^''e {N.V) is normal and its relations are 

 well brought out in figures 24 to 37. 



The abducent nerve (N.VI, figs. 32 to 36) shows no departure 

 from the normal. The connection between its nucleus (N'u.N'. VL) 

 and the superior olive {N'u.o.s.) is also to be made out. 



The facial nerve {N.V 11, figs. 32 to 39) is normal in all its 

 relations. The emergent fascicles on the right side are arranged 

 around a small artery. 



The vestibular nerve {N.VIII, vest., figs. 32 to 39) is normal in 

 its relations and connections. The cochlear nerve (N.VIII, 

 coch) is also normal and the dorsal and ventral cochlear nuclei 

 are quite evident (Nu.coch.d. and Nu.N.coch.). The corpus trap- 

 ezoideum (c.t.), superior olive (Nu.o.s.) and lateral lemniscus (L.l.) 

 are well shown, and the continuity of the superior olive with the 



