THE CRANIAL NERVES OP SCYLLIUM. 123 



Fi°\ 11, drawn to show the whole course and relations of the 

 fifth nerve and its connections with the third and seventh 

 nerves. The figure also shows the fourth nerve, and the 

 terminal distribution of the hyoidean branch of the seventh. 

 Fig. 12 shows the whole course of the seventh nerve and its 

 branches, with the exception of the hyoidean branch 

 (shown in the preceding figure) ; also the course and 

 distribution of the ninth nerve, and certain branches of 

 the fifth and tenth nerves. 



Fig. 13. Longitudinal and vertical section through the head of an 

 embryo of stage n ; the figure, which is taken from two 

 consecutive sections, shows the origin and main trunk of 

 the third nerve, the root of the fourth, and the roots, 

 course, and distribution to the rectus externus of the sixth 

 nerve, x 20. 



Figs. 14 & 15. Diagrammatic longitudinal and vertical sections 

 through the head of an embryo of an age intermediate 

 between stages o and p. x 15. 

 Fig. 14 shows the roots of origin of the third, fifth, and 

 seventh nerves together with the course and distribution 

 of certain of their branches and the mutual connections 

 between these three nerves. 

 Fig. 15 shows the dorsal root of the seventh nerve, the 

 ophthalmic branches of the fifth and seventh nerves, the 

 ramus ophthalmicus profundus, the fourth nerve, the 

 maxillo-mandibular branch of the fifth, and the buccal and 

 palatine branches of the seventh. 



Fig. 1 6. Transverse section through the head of an embryo of stage 

 q, shortly before the period of hatching. Shows the origin, 

 course, and distribution of the fourth nerve, and its close 

 proximity to the ophthalmic branches of the fifth and 

 seventh nerves, x 10. 



Fig. 17. Diagrammatic longitudinal and vertical section through the 

 head of an embryo of stage n. Shows the position and 

 arrangement of the segmental cranial nerves, x 20. 



