458 



HISTORY OF THE HUMAN BODY 



the Hypoglossus, but this has not yet been definitely shown. 

 The Hypoglossus enters into connection with one or two of 

 the first cervical nerves, forming the ansa hypoglossi, a union 



-xi gang crest 



div 



$up max tii 

 /V masticator/us 

 JnrTmax.d 



FIG. 125, 0. Reconstruction of peripheral nerves in human embryo. 

 [After STREETER.] Four weeks human embryo, 6.gmm long. 



N. tymp, tympanic nerve; N. laryg. sup, superior laryngeal nerve; Gang, petros, 

 ganglion petrosum; Gang nodos, ganglion nodosum; Fronep, Froriep's ganglion. 

 The cranial nerves are designated by roman numerals, the spinal by arabic. The 

 other designations are evident. 



from which proceed motor nerves to certain of the hyoid and 

 extrinsic laryngeal muscles. 



It is now time, after this review of the cranial nerves and 

 their morphological history, to take up the question of the 

 original segmentation of the vertebrate head, and consider what 

 light the nerves throw upon this obscure and much-disputed 

 subject. 



