\'. KuPFFEK, Cranial Nerves of \ ertcbratcs . 257 



between brain and epidermis, forming the well-known 

 ganglion- or nerve-" border" (Leiste) of writers, and now it 

 becomes necessary in considering the development of the 

 cranial nerves to keep distinctly in mind the different 

 regions. 



I distinguish accordingly: ( i ) The region of the fore head 

 to the eye, inclusive; (2) the fore gill region, comprising the 

 mouth and the three fore gill pouches; (3) the hind gill 

 region to the eighth gill pouch, inclusive; (4) the trunk 

 region. 



In the region of \k\.e. fore head (Fig. 3) begins the forma- 

 tion of the borders (Leiste), which I designate as root- 

 borders ( Wurzelleiste), from the dorsal brain-plate, before 

 the formation of the eye has begun; and the cells soon 

 extend along the whole lateral surface of the fore-brain, 

 whereby the connection with the brain here becomes severed. 

 These cells are at first rounded, then become spindle-shaped 

 and touch each other, so that they appear in connected 

 layers. They are ranged mostly in two rows, but so that in 

 one place a larger collection always shows itself. In my 

 treatise I gave a figure(') of this, indicated this accumulation 

 as a ganglion, and regarded it as the first rudiment of the 

 first trigeminus ganglion. That it behaves like the rudiment 

 of a ganglion I still hold, but I have come to doubt whether 

 it goes into the first trigeminus ganglion or forms the first 

 spinal ganglion, to be mentioned later. The determination 

 is difficult, and requires more extended and especially more 

 comparative investigations. But the whole mass of cells 

 does not in every case collect itself into a compact ganglion, 

 but it arranges itself in lines, which, after the appearance of 

 the sense organs, extend both towards the nose and eye and 

 also towards the hypophysial pouch. Later they unite, in 

 the main, with the first trigeminus ganglion, whose branches 

 they appear. 



t Arch. f. Mikrosk. Anat., B<1. 35, 1890. Taf. XXFX, Fig. 39 g). 



