232 JOURNAL OF COMPARATIVE NEUROLOGY. 
‘When the percentage values of these numbers are found, 
they give the following: 
TABLE VIII 
Average for first Average for second Average for all. 
Segment. 3 entries 3 entries 6 entries. 
Thigh 36.5% 36.5% 39.5% 
Shank 25.0% 25.8%, 25.4% 
Foot 38.5% 37-7% 38.1% 
On attempting to apply these percentages in the calcula- 
tion for the supply to the leg, it was found that the numbers 
obtained were somewhat larger than we expected them to be 
in the case of the thigh. It appeared that the area for the 
thigh had been over-estimated. Dr. Dunn therefore undertook 
a reinvestigation of the innervation of the skin of the thigh. 
This showed that the area was over-estimated in this sense, that 
in addition to the fibers entering the leg by the sciatic and 
crural nerves. there was a small independent bundle of nerves 
which entered through the anus and was distributed to a small 
triangle of skin just behind the anus and on the mesal surface 
of the leg. The area of this piece of skin thus innervated, 
was found to be 2.5% of the area of the entire thigh. For 
the details of this determination the reader is referred to a 
forthcoming paper by Dr. Dunn. 
To control these results, other measurements were made 
by an entirely different method. A plaster mould of the frog’s 
leg was taken and the leg then cast in Woops metal. On this 
cast the thigh and shank were examined for their respective 
areas by winding them carefully with fine copper wire—of a 
uniform diameter. The diameter being constant, the areas 
covered by the wire would be directly proportional to the 
length or weight of the wire used. The relations were tested 
by weighing the wire. The weight of the wire needed to 
envelop the thigh, was to that needed to envelop the shank 
as 1.43: 1. 
On comparing this ratio with that from the areas for the 
thigh and shank, as shown in Table 7, it appears that this ratio 
is also 1.43: I. 
Thus the proportional areas for the thigh as determined 
