562 SHINKISHI HATAI 
characters may arise when the two parental characters blend 
together with equal potency and the limiting case of such dis- 
tribution leads to the normal probability curve. The brain 
weights here investigated may thus be taken as a good example 
of the limiting case of the formula of the blending inheritance, 
where dominance is absent. 
FREQUENCY | 
> CI 
BRAIN WEIGHT 
7 
lA 
8 
PEE 
Beepeseeesz=can 
BREE 
EEEEEE CEE 
Ht es 
15 HH iv 
a 
ihn oa 
OSES RooD fa isp 
70 FA ao 
seeerde auth i 
C1 eo 
of rm 
5 
ra Hf 
CCA Ni a 
o4an POS CL 3a 
p LO EAL cas ClCH co 
140 NIGHTS 92° 24 14e  AIGH 1B Oe eens 
BRAIN WEIGHT GMS BRAIN WEIGHT GMS 
CHART 2 
COAT COLOR AND BRAIN WEIGHT 
It may be added that in the F, generation we usually obtain 
five varieties of coat color in rats; self gray, black, gray piebald, 
black piebald and albino (see Bateson, ’09). In our experi- 
ment the mortality was somewhat large and in as much as the 
inheritance of the coat color was not the object of the present 
experiment, the census of the coat colors of the dead rats was 
unfortunately not taken. We find however from an examina- 
tion of the final records 42 albino and 107 pigmented rats, or a 
proportion of 1 albino to 2.6 pigmented, thus coming very close 
