V. KuPFFER, Cranial Nerves of Vertebrates. 32;^ 



to the praetrematics of the gill region, and it is worth noticing 

 that such a one lies in front of the stomodaeum. 



Since at least one epibranchial ganglion participates in 

 the formation of the N. mandibularis, as well as of the N. 

 maxillaris, I regard both nerves as homodynamous to at least 

 one branchial nerve, but reserve a final judgment as to their 

 value. 



I cannot clearly demonstrate a participation of the first 

 epibranchial ganglion, impinging upon the lens, in the 

 formation of peripheral nerves. 



SPINAL SYSTEM OF CRANIAL NERVES. 



The determination of the parts of this system encounters 

 great difficulties. The somites, which ^re present only a 

 short time between the ear and eye, already dwindle away 

 a perceptible time before the exit of the embryo, and with 

 them the dorsal branches of the dorsal spinal nerves. The 

 principal ganglia of the branchial system, the eye and the 

 lateral muscles of the head growing cephalad take up so 

 much space that the spinal nerves have to be sought in 

 narrow interspaces. In every case they are less developed 

 than those of the branchial system. One does not meet com- 

 pact cords in the developmental stage under consideration, 

 but only loose strands of fibrillae connected with cells. One 

 applies himself with more advantage to the ganglia than to 

 the roots for the determination of their number and arrange- 

 ment. 



One encounters the foremost ventral spinal nerve, the 

 root and the little ganglion of a dorsal spinal nerve, which I 

 regard the foremost almost in a single transection (Fig. 10, 

 vs, ds). This spinal ganglion lies between the secondary 

 optic vesicle and the brain. In a cross section close behind 

 this there lies a second ganglion, ventrad from the first, on 

 the outer wall of a blind extension of the aorta. It is con- 

 nected with the first, and I can regard it only as the foremost 

 sympathic ganglion. 



