8o Journal of Comparative Neurology. 



The relations existing between the two roots, as shown here, 

 correspond in the main with those found by Birge. 



1. The number of dorsal root fibers in the same animal 

 is greater than that of ventral root fibers. A frog of 48 grams 

 has for one side approximately 8572 dorsal root fibers against 

 62 1 1 in the ventral roots. This is an excess of 38%. This 

 excess in the dorsal roots however is greater than that obtained 

 by Birge in a frog of 63 grams. 



2. The apportionment of fibers to the different roots is 

 widely different. Only in case of the 1st, Ilird and Xth nerves, 

 do ventral root fibers exceed those of the dorsal root. In the 

 remaining nerves, dorsal root fibers predominate, but in very 

 unequal degrees. Of all the nerves here investigated, the great- 

 est percentage of dorsal root fibers in excess of those of the 

 ventral root is found in case of the Vllth nerve. In Table I 

 this nerve possesses an excess of 178% and in Table II an ex- 

 cess of 214%. 



The percentage values of the excess of the larger root of 

 each nerve represented in Chart II are given in Table V. For 

 contrast the cases in which the ventral root contains the greater 

 number of fibers are placed in a separate column. 



TABLE V. 



The percentage values given in Table V are presented in 

 the form of a curve in Chart III. In the Chart the cases of an 

 excess of dorsal root fibers are recorded above the base line and 

 those of an excess of ventral root fibers below it. It is seen 



