582 'Journal of Comparative Neurology and Psychology. 



in short branches or knobs. It is seen that the fibers do not 

 penetrate far into the myotome but spread around the ends of the 

 myotome in the intermuscular septa. Here the end plates are 

 found and it may be said that most of these endings stand in 

 relation with the ends of the muscle fibers. To understand the 



Fig. 14. A horizontal section of part of the left half of the body passing through the notochord 

 to show the relation of the motor fibers to the myotomes, d.r., dorsal roots; v.r., ventral roots, m., 

 myotomes, s., intermuscular septa; nch., notochord. In the intermuscular septum above, a musculo- 

 sensory ending ( ?). At A is shown the cross section of the right half of the spinal cord at the same 

 magnification as the rest of the figure. The motor cells and the Miillerian fibers may be compared with 

 the peripheral motor fibers. Magnification, 40 diameters. 



disposition of the fiber drawn in fig. 15 it must be remembered 

 that the inner surface of the myotomes slant obliquely outward 

 and downward from the vertebral region, so that the endings 

 shown actually lie on the ventro-mesal surface of the myotomes, 

 and are drawn as if seen through the mesal part of the myotomes. 

 I have not drawn any of the end plates of these fibers at a high 



