106 J. B. JOHNSTON 



preted the entire structure as the equi\'alent of the iiervus 

 terminahs of fishes. 



Dollken's paper has come into my hands since the present 

 manuscript was finished and the figures drawn. Dollken's de- 

 scription of the nervus terminalis and ganglion terminale in 

 mouse, rabbit, and human embryos is in essential agreement with 

 the above account for the pig, sheep and man. The central con- 

 nections of the root may be passed over briefly. Only Dollken's 

 root c ending in the septum corresponds to the root seen by me. 

 The continuity of nervus terininalis roots with fibers leading to the 

 gyrus fornicatus and hippocampus seems to the writer to recjuire 

 confirmation. It is not clearly demonstrated in Dollken's figures. 



Dollken apparently regards the nervus terminalis as the special 

 nerve of the \'omero-nasal organ. He describes a part of its 

 fibers at least as arising from cells in the vomero-nasal epithelium. 

 He uses the name ganglion terminale as synonymous with 'gan- 

 glion vomero-nasale' of de Vries and 'Nebenbulbus' of v. Gudden, 

 Kolliker and others. "Am oralen Ende der Hemisphare liegt 

 medial das Ganglion terminale (Ganglion nasale, Ganglion vo- 

 mero-nasale, Nebenbulbus)." From this it would appear that 

 he considers the ganglion terminale as the primary center for the 

 vomero-nasal nerve and he has been so understood by McCotter 

 ('12, pp. 302, 316). This is, however, wholly inconsistent with 

 Dollken's clear description of roots from the ganglion terminale 

 to the paraterminal body and other regions of the hemisphere, 

 and with his comparison of the cells of the ganglion terminale 

 with those of spinal and cerebral ganglia (p. 23). On the other 

 hand, it appears very probable to the writer that Dollken has 

 failed to recognize the clear distinction which exists between the 

 ganglion terminale and the cells lying among the olfactory nerve 

 fibers ('olfactory ganglion') which later produce neurilemma cells. 

 Comparison of his figures 1 and 2 with the conditions in the pig 

 (figs. 1 and 3 of this paper) suggests that Dollken has in view 

 in these stages of the mouse chiefly or solely olfactory fibers 

 entering the formatio bulbaris and that the ganglion terminale 

 of these figures is only the 'olfactory ganglion' of older authors. 

 The apparent reduction in the number of ganglion cells in the 

 course of the nerve in later mouse embryos (p. 17) would be 



