SYMPATHETIC NERVOUS SYSTEM IN MAN 201 



The writer desires at this time to call attention to an error in 

 his earlier work on the development of the otic ganglion in 

 embryos of the chick ('14). In this instance the tympanic nerve 

 was not recognized as a path along which cells migrate cephalad 

 from the petrosal ganglion. The fibrous ramus which emerges 

 from the plexuses on the internal carotid artery to join the tym- 

 panic nerve in the formation of the lesser superficial petrosal 

 nerve is relatively large in embryos of the chick and shows some 

 migrant cells. Having no sagittal sections of the earlier stages 

 at hand, it was erroneously concluded that the majority of the 

 cells which enter the otic ganglion advance from the plexus on 

 the internal carotid artery. The writer is now of the opinion 

 that relatively few if any cells reach the otic ganghon from this 

 source, but that in embryos of the chick, as in mammalian em- 

 bryos, the cells which enter the otic ganglion from other than 

 trigeriiinal sources advance along the lesser superficial petrosal 

 nerve primarily from the petrosal ganghon. A contribution of 

 cells to the otic ganglion from trigeminal sources is less obvious 

 in embryos of the chick than in mammalian embryos. Never- 

 theless, in the light of comparative studies, it cannot be excluded. 



Broman('ll) and Streeter ('12), who studied the development 

 of the otic ganglion in human embryos, and Ganfini ('17), who 

 employed embryos of other mammalian types (guinea-pig and 

 pig) , concur in the opinion that this ganglion is derived exclusively 

 from the semilunar ganglion. On the other hand, Stewart ('20), 

 basing his conclusions on observations made on embryos of the 

 pig and the rat, maintains that the otic ganglion arises exclusively 

 from cells which advance peripherally along the lesser superficial 

 petrosal nerve. 



Submaxillary ganglion 



The primordium of the submaxillary ganglion arises relatively 

 early in human embryos as an accumulation of cells in the path 

 of the lingual division of the mandibular nerve. In embryos 10 

 to 11 mm. in length in which only the merest traces of the pri- 

 mordia of the sphenopalatine and otic ganglia are present the 

 primordium of the submaxillary ganglion has already attained 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 32, NO. 2 



