186 NAOKI SUGITA 
weight and taking averages for each group. Group I consists 
of those which have brains weighing less than 1.0 gram and pre- 
sumably still in the first phases of cortical development (Sugita, 
"17 a) and Group II those which have brains weighing more than 
1.0 gram and probably in the second or third phase of cortical 
development. So, one litter in Series I was divided into four 
groups, the tests having brain weights less than 1.0 gram (T. I), 
the tests having brain weights more than 1.0 gram (T. II), the 
controls having brain weights less than 1.0 gram (C. I) and the 
controls having brain weights more than 1.0 gram (C. II). 
This grouping prevails throughout all condensed tables (tables 
3 to 13, 16 and 17) published in this paper. The average values 
were all obtained according to individual measurements, and the 
average standard values were also obtained by averaging from the 
full tables, which give the individual cases. As the standard 
values were not based on the average measurements given in the 
condensed tables, those standards given in the condensed tables 
sometimes deviate slightly from the standard values which 
would be directly obtained for the given average measurements. 
On comparing, in table 3, the observed measurements with the 
corresponding standards, no significant difference between them 
has been detected, either in the underfed or in the controls, 
Only the body weight in the underfed is slightly lower as com- 
pared with the standard for the same body length, but it amounts 
to no more than 8 per cent. 
This comparison indicates that, though the underfed young 
show a considerable retardation in total growth according to age 
(see table 4), yet the relation between the body and the tail 
lengths and the body weight is but little affected, at least during 
the early period of active growth. So the only marked differ- 
ence between the underfed and the controls of the same body 
length or body weight would be the age, if their brain weights are 
disregarded. The effect on the brain weight will be discussed 
in the next chapter. 
