899 



Aufsätze. 



Nachdruck verboten. 



A contribution to the morphology and derelopment of the 

 nervous system of Vertebrates. 



By J. Beaed. 



Aus dem Anatomischen Institut zu Freiburg i. Br. 



(Schluß.) 



I have entered more fully into the formation of these two inter- 

 esting ganglia and their sense organs elsewhere, and I can here be con- 

 tented with the remark that the evidence appears to me to accumulate 

 in favour of my former conclusions as to the morphology of nose and ear. 



As to the olfactory ganglion, the existence of which Prof. Gegen- 

 BAUR denies, I venture to suggest that although the comparative ana- 

 tomist may not find one, — if he looked at Jacobson's organ in any 

 common Snake he would find a number of ganglia — the embryologist 

 has little or no difficulty in demonstrating such a ganglion in, for 

 example, Elasmobranch and Reptilian embryos. 



The spinal ganglia in Elasmobranchs, Amphibia, Rep- 

 tilia and Mammalia. 

 I can make short work of the description of the development in 

 all these types, including the Frog, by simply stating that the spinal 

 ganglia develop exactly as I have described in the Chick. 



The cranial ganglia in the Lizard, Triton, and Rabbit. 

 The development is here essentially that described in Sharks with 

 the slight exception that the lateral or branchial sense organ Anlagen 

 are more or less rudimentary and embryonic, or larval, structures. 



The cranial ganglia in the Frog. 

 The neural ganglia are formed as in Sharks, the lateral ganglia 

 are formed from the inner layer of the epiblast and, unlike any 

 other type examined they separate from the epiblast 



