CRANIAL SYMPATHETIC GANGLIA IN THE PIG 



77 



Oculomotor nerve 



The oculomotor nerve emerges from the wall of the mesen- 

 cephalon by several slender rootlets arranged in a longitudinal 

 series (fig. 4, Oc). The proximal part of this nerve, in sagittal 

 sections, therefore, appears distinctly fan-shaped. Throughout 



Fig. 3 Section showirg the motor root of the trigeminal nerve in an embryo 

 of the pig 11 mm. in length. EL, external limiting membrane; MC, migrant 

 medullary cells; MR, motor root. 



Fig. 4 Section showing the oculomotor nerve in an embryo of the pig 8 mm. 

 in length. Cil, ciliary ganglion; FB, fore-brain; Inf, infundibulum; HB, hind- 

 brain; M, mid-brain; Oc, oculomotor nerve. 



Fig. 5 Neuroblasts (drawn under oil immersion lens with aid of camera 

 lucida). A, observed in mesenchyme between ophthalmic nerve and ciliary 

 ganglion, embryo 14 mm. in length, B, C, D, observed in ophthalmic nerve, 

 embryo 14 mm. in length. 



the entire length of the growing nerve, its fibers are accompanied 

 by cells obviously of medullary origin. These cells are identical 

 in appearance with the cells which, as indicated above, advance 

 peripherally from the semilunar ganglion and from the wall of 



