128 CHARLES BKOOKOVER 



,<ili;i \v(M-{> foiiiul. Perhaps in these instances the ganglionic mass 

 was not included on account of its posterior position along the 

 olfactory nerve, as in the previously-described fish measuring 

 85 mm. in length. In figure 17 is shown, by a flat reconstruction 

 from sagittal sections stained with toluidin blue, the distribution 

 of what were interpreted as peripheral ganglia of the nervus termi- 

 nalis. A similar distribution was found in a series treated by the 

 vom Rath method. In these specimens one or two larger clumps 

 of ganglion cells are embedded in the main olfactory nerve or 

 between its main rami, and other smaller ganglia are situated 



NASAL EPITHELIUM 



GANGLIA OF NERVUS TERMINALIS 



Fijr. 17 Flat reconstruction from sagittal sections of the nasal capsule anci 

 olfactory nerve of adult fish to show the relative position of the peripheral ganglia 

 of the nervus terminalis to the olfactory nerve and nasal mucosa. X 10. 



near the base of the main folds of the olfactory mucosa, along the 

 branches of the olfactory nerve (fig. 17). These peripheral ganglia 

 did not show well-marked Nissl granules, but this was attributed 

 to the fact that the fishes available were kept empounded for 

 some time and were not in the best of physical condition. How- 

 ever, there seems to l)e little doubt that these are ganglion cells, 

 when we consider the embryological history given above and the 

 similar position of ganglion cells in other fishes. 



In the way of sunnnary and conclusion, we may say in brief 

 that in Lepidosteus the nervus terminalis ganglion cells seem to 

 arise from the olfactory placode in a way similar to that described 

 by us for Amia and Ameiurus in previous papers. The ganglion 

 appears late in embryonic history, in close relation to the vasciilai' 

 tissues, and still later, in Lepidosteus becomes divided into a 



