192 ALBERT KUNTZ 



To what extent cells which advance peripherally along the vagi 

 take part in the development of the enteric plexuses in the more 

 distal portions of the intestine is not clear. The evidence at 

 hand favors the conclusion that the primordia of these plexuses 

 gradually extend distally from the upper levels of the intestine 

 in which the cells are certainly derived from the vagus supply. 

 On the other hand, the lower portions of the intestine, especially 

 the large intestine, arises in close proximity with the preverte- 

 bral plexuses in the lower abdominal and pelvic regions. Paths 

 along which sympathetic cells may migrate from these plexuses 

 into the walls of the intestine are established relatively early. 

 Obviously, the enteric plexuses in the lower portions of the in- 

 testine are derived from the sympathetic supply in the lower 

 trunk region. 



CRANIAL SYMPATHETIC GANGLIA 



Ciliary ganglion 



Doubtless the ciliary ganglion represents the most primitive of 

 the well-defined sympathetic ganglia in the cranial region in the 

 higher vertebrates. Its development has been studied in em- 

 bryos of types of all the classes of vertebrates. The majority of 

 the more recent investigators, including the present writer, have 

 agreed that this ganglion arises from cells of cerebrospinal origin 

 which advance peripherally both along the oculomotor and oph- 

 thalmic nerves. However, both Broman ('11) and Streeter ('12) 

 failed to recognize cells which advance peripherally along the 

 oculomotor nerve and enter the primordium of the ciliary gan- 

 glion in human embryos. They derived the ciliary exclusively 

 from the semilunar ganglion. Ganfini ('17) pointed out that 

 the contribution of cells from the oculomotor nerve to thfe ciliary 

 ganglion is much less obvious in mammalian embryos (guinea-pig 

 and pig) than in embryos of types of other classes of vertebrates ; 

 however, inasmuch as its double origin is clearly established in 

 other classes of vertebrates, he concluded that this ganglion is 

 genetically related both to the oculomotor and ophthalmic nerves 

 also in mammals. Although Stewart ('20) maintains that all 

 the other cranial sympathetic ganglia arise exclusively from cells 



