NERVUS TERMTNALIS IN REPTILE AND MAMMAL 109 



cells in the ganglion as he implies in his conclusions (p. 114). 

 If they are axones of peripheral ganglion cells, they are best 

 regarded as receptive fibers, as the writer has considered them in 

 other fishes. That some of the cells derived from the olfactory 

 placode along with the ganglion terminale should develop into 

 sympathetic ganglion cells is no more than might be expected 

 in view of the origin of sympathetic ganglion cells from the spinal 

 ganglia. Whether any sympathetic roots remain connected with 

 the telencephalon as a component of the nervus terminalis is 

 still uncertain. 



The continuation of some of the fibers of this nerve in urodeles 

 to the hypothalamus and probably to the interpeduncular region 

 of the mesencephalon as described by McKibben is very remark- 

 able. Taken together with the apparent absence of a ganglion 

 terminale this suggests the hypothesis that these may be efferent 

 (sympathetic) fibers such as Brookover supposed to be present 

 in Amia. Upon this point the writer would offer the observation 

 that in a 35 mm. larva of Amblystoma punctatum collections of 

 ganglion cells are found on two of the three branches of the olfac- 

 tory nerve which supply the vomero-nasal organ. In view of 

 the discussion over the vomero-nasal organ of amphibians it 

 should be said that the development of the organ has been traced 

 in Amblystoma. It arises as a medial diverticulum from the 

 ventral part of the thick olfactory epithelium of the nasal sac a 

 short time before the choanae are open into the mouth. Later 

 a rotation of the nasal sac and the vomero-nasal organ takes 

 place, such that this organ comes to hold the relations of a lateral 

 diverticulum in the 35 mm. larva. The diverticulum very early 

 gives rise to branched tubular glands which extend medially and 

 lie ventro-medial to the nasal sac. The nerve supply here de- 

 scribed is further evidence that this diverticulum is the homologue 

 of the vomero-nasal organ of reptiles and mammals, as held by 

 Burckhardt, Seydel, Hinsberg and others. (For the literature, 

 see Peter '02). The small ganglia mentioned above lie near the 

 vomero-nasal organ and correspond to the ganglia seen near the 

 ends of the branches of the nervus terminalis in turtle embryos. 

 As described by McKibben the nervus terminalis is imbedded in 

 the olfactory nerve and its peripheral course was not seen. The 



