V. KuPFFER, Cranial Nerves of \^ertebrates. 329 



in Torpedo, whereby the perception of their separate origin 

 is rendered difficult. This being the case, Beard's lateral 

 ganglia would correspond to the lateral and epihranchial 

 ganglia together in my sense. A renewed investigation of 

 the development of the , cranial nerves of elasmobranchs is 

 necessary to obtain clearness here. 



Froriep's communications are much more intelligible. In 

 the youngest cow embryos on which he began his investiga- 

 tions, the principal ganglia were already formed and re- 

 moved from the epidermis, so only the formation of the epi- 

 hranchial ganglia could be treated of, the rudiments (Anlage) 

 of which exist in Froriep's " gill cleft organs." The thick- 

 ened patches of epidermis behind the eye in young cow 

 embryos, mentioned by him, I might pronounce without 

 hesitation to be the rudiments of the foremost epihranchial 

 ganglia. 



So that I could express from personal inspection an 

 opinion upon the mode of formation of the cranial nerves in 

 Amniota, I have commenced a piece of work in the Institute 

 of this place upon bird embryos, which, begun not long 

 ago, already has led to the result that there exists essentially 

 a complete agreemefit zvith the processes in Cyclostomes . The 

 duck appears to furnish an especially suitable object. It has 

 become apparent that the rudiments of the cranial nerves 

 proceeding from the root-border ( Wurzelleiste) divide into 

 the spinal and branchial nerves, and that these branchial 

 nerve rudiments, while they are yet mainly composed of 

 cells, grow distally between epidermis and proto vertebrae, 

 and on the one hand fuse with the epidermis for the forma- 

 tion of the principal ganglia, on the other hand, after the 

 separation of the principal ganglia from the epidermis, enter 

 into a second connection with it over the gill pouches. 



This work has not progressed far enough to enable me to 

 go into particulars, but this much may be said, that in the 

 trigeminus region also the typical mode of development is 

 preserved, since in the formation of the first principal gan- 



