CRANIAL SYMPATHETIC GANGLIA IN THE PIG 83 



ment. In parasagittal sections of embryos 12 to 15 mm. in 

 length, small groups of cells of ganglionic origin may be observed 

 along the median surface of the maxillary nerve. Some of these 

 cell-groups lie distinctly within the path of the nerve, while 

 others lie in close proximity with its surface. These loosely 

 aggregated cell-groups represent the anlage of the sphenopalatine 



OpI 





Fig. 8 Parasagittal section through orbit, embryo of cat 22 mm. in length. 

 Cil, ciliary ganglion; Oc, oculomotor nerve; Oph, ophthalmic nerve; OS, optic 

 stalk. 



Fig. 9 Parasagittal section near median surface of maxillary nerve, embryo 

 of pig 19 mm. in length. Ma, maxillary nerve; 0, oral cavity; S, semilunar 

 ganglion; Sp, sphenopalatine ganglion. 



ganglion. As development advances, these cell-groups become 

 larger and push out farther peripherally along the path of the 

 growing nerve. In embryos of the pig 19 mm. in length, as 

 illustrated in figure 9, *Sp, an irregular mass of loosely aggregated 

 cells is observed beginning but a short distance from the periph- 

 ery of the semilunar ganglion and stretching along the median 



