1/6 Journal of Comparative Neurology. 



I 



dorsal portion of the " dorsal seventh " enters ; and these bun- 

 dles are coextensive with that area. In the region of the fifth 

 nerve, arcuate fibers are intimately connected with the diminish- 

 ing number of myelinic fibers in the dorsal tracts. Some of 

 these seem to cross in the raphe and turn into the cinerea of 

 the opposite side. 



Oiigin of the Cranial Nerves. (Figs. 5, 9-20, 22.) At 

 the time this investigation was undertaken the condition of our 

 knowledge of the origin of the cranial nerves of the tailed Ain- 

 pJiibia was far from satisfactory. Fragmentary results had been 

 obtained by Stieda ; more complete were the observations on 

 this subject made by Osborn ; still, some evident inconsistencies 

 in his results with those reached on other forms, and a failure 

 to recognized the true relations of certain nerves, rendered a 

 review of the subject desirable. In respect to the homology 

 of the nerve components, as stated by him, interpretations de- 

 pended largely on the peripheral relations and distributions of 

 the several components, of which nothing satisfactory was 

 known. The papers of Strong, however, have supplied the 

 necessary information ; not only has he investigated the distri- 

 bution and segmental value of the components but also made 

 extensive comparisons with the cranial nerves of other Ichihy- 

 opsida. The ental or deep origins have also been discussed by 

 him, rendering less necessary an extended description here ; 

 however, as the results here attained confirm, and in part sup- 

 plement his, they are, in so far, at least, of value and will be 

 given. Where possible, the roots in Nectiirus have received the 

 names applied by him. Instead of the terms motor and sensory 

 nuclei or nidi, the recent reSults of the impregnation methods 

 render preferable a terminology in which the relations of fiber 

 and cell are more distinctly implied, and here will be employed 

 those adopted by Kolhker ('93) (" Endkern " and " Ursprungs- 

 kern ") and Turner ('94), " nucleus of origin " and " terminal 

 nucleus" nidiis being employed in preference to nucleus. It is 

 evident that the nidus of origin of sensory nerves would be the 

 peripheral ganglia from the cells of which their fibers spring, 

 and the ' terminal nidus ' within the brain, with which they 



