THE DEVELOPMENT OF THE CRANIAL NERVES 

 OF VERTEBRATES.(') 



Prof. C. von Kupffer. 



Tracing their origin, these cells are seen to proceed from 

 the epidermis. The latter thickens by elongation of its ele- 

 ments, which then divide transversely, after which the ental 

 layer of daughter cells do not reassume their epithelial 

 arrangement, but constitute the special sub-epidermal layer 

 or neurodermis. The latter has in any case a close relation 

 with the development of the peripheral part of the branchial 

 nervous system, evidence of which is furnished by the fact 

 that the thickening of the epidermis, which precedes the 

 development of this structure, is derived from the rudiment 

 of the epibranchial ganglion. 



It is cells of this layer which furnish the first commissures 

 connecting the epibranchial ganglia with each other, as well 

 as with the preformed branchial nerves and with the defini- 

 tive (principal) ganglia. It may, therefore, be said that the 

 epidermis contributes to the development of the peripheral 

 branches of the branchial system, but whether these cells 

 play a r6le in the formation of the fibrillae, or simply have a 

 secondary significance, cannot be determined at present. 



CRANIAL NERN'ES OF YOUNG AMMOCCETES. 



After this exposition of the main features in the develop- 



Translated for this journal, from advance sheets, by Oliver S. Stroni;, Fellow in 

 Biology in Columbia College. 



