156 Journal of Comparative Neurology. 



whole cervix columnae posterioris and dorsal portion of the 

 columna anterior and were considered as belonging to this type 

 (central or intermediate neurones) rather than as peculiar to 

 the nucleus dorsalis. These may be concerned with the neu- 

 rones of the nucleus dorsalis proper, but only as neurones 

 whose axones are of short course and serve as association and 

 commissural pathways for the segment containing them. As 

 such, they were not included in the counts. 



Erom the foregoing observations upon the nucleus dorsalis 

 of the elephant the following conclusions are advanced : 



1. The afferent axones from the radices posteriores enter 

 the nuleus dorsalis more abundantly in the caudal end of the 

 Ilnd thoracic segment than in any segment between this and 

 the Vlllth thoracic inclusive. 



2. That some of these afferent axones pass caudad to 

 terminate in the nucleus dorsalis at other levels. 



3. That, in addition to the above mentioned axones and 

 the cell-bodies proper to it, the nucleus dorsalis contains many 

 other longitudinally coursing medullated axones giving it the 

 appearance of a compact fasciculus rather than a nucleus. 



4. That these latter axones increase in abundance in pass- 

 ing from thoracic VIII to thoracic II and that in all probability 

 the cell bodies peculiar to the nucleus do the same. 



5. That in the caudal portion of thoracic II, there is a 

 sudden disposition on the part of the axones coursing in the 

 nucleus dorsalis to leave its confines, passing obliquely cephalad 

 across the cervix of the columna posterior to enter the funiculi 

 laterales, probably to form the fasciculus cerebello-spinalis. 



6. That with the departure of these axones the nucleus 

 dorsalis becomes smaller, its cell bodies fewer, and that it dis- 

 appears in the 1st thoracic segment. 



As to the grouping of the cell bodies in the columna an- 

 terior, little can be said. In other animals the grouping gener- 

 ally described is more evident in the cervical segments. Here for 

 the elephant, in the same segment, some sections will show a ten- 

 dency toward grouping not displayed in others. In general it 

 may be said that the cell-bodies are very numerous but that 



