Dunn, Innewation of the Thigh in the Frog. 



237 



TABLE XII. 



Showing for the Crural Nerve, and the Sciatic Nerve above and below its 

 branches to the thigh, the area, the number of fibers and the average area for 

 each nerve fiber. 



I . Average area for each fiber innervating the thigh. 



The nerve fibers to the thigh naturally fall Into two divis- 

 ions, those which arrive by way of the crural nerve and those 

 which traverse the sciatic pathway, and these in turn re-group 

 themselves, according to their destinations, into muscular and 

 cutaneous fibers. 



Directing attention to the determination of areas in the 

 crural nerve, we find that the branches easily adapt themselves 

 to the muscular and cutaneous classification, as they contain 

 either purely muscular or purely cutaneous fibers. Using this 

 arrangement for our tabulation we find, Table IX, that frog B 

 has 619 fibers in its cutaneous branches to the thigh of the left 

 leg. The area of these branches is .085 of a square millimeter. 

 By process of division the area for each fiber is found to be 137 

 square micra. The muscular branches for the same region con- 

 tain 372 fibers and have an area of .066 of a square millimeter. 

 By a like process of division the average area for each muscular 

 fiber is found to be 177 square micra. 



The total number of fibers for the left thigh is 991 and the 

 area .151 of a square milHmeter, giving an average area of 152 

 square micra for each nerve fiber of the left crural nerve in frog 

 B. The numbers for the right crural nerve of the same frog 

 are very similar and give an average area of 153 square micra 

 for each nerve fiber. 



