558 SHINKISHI HATAI 
Albino rat. In the albino rat with a body length of 194 mm. 
we obtain an observed average brain weight of 1.740 grams. 
The formula gives however 1.827 grams for the body length of 
194 mm., thus the observed brain weight is 4.65 per cent less 
than the value given by the formula. The computed brain weights 
for the Albino which appear in chart I were obtained by sub- 
tracting 4.65 per cent from the values given by the formula. 
These computed values for the Norway and albino rats were 
taken as the basis for estimating the positions which the brain 
weights of the hybrids occupy. 
TABLE 1 
Showing the data on the body length and brain weightsin both the norway and albino 
rat used as parents 
Norway M. X albino F. = 9 cases 
Norway F. X albino M. = 5 cases 
Norway rats Albino rats 
x0. Se le oe ee ame 
mm. gms. mm. gms. 
bt eeeen Ree M. Dak DOA! Nii Hinere tere 2 190 1.596 
(OS Rinsho Ke 208 Badal: “\IMy. oe 205 1.807 
etree cerns F. 215 D2 (OP a) IM ts ee 209 1.937 
Ob wees oer sae M 267 PENOO.. -| Byes aon 180 1.702 
Ne F 202 MOO ier || IIE ane. 208 1.827 
Aree As oneal, IR 214 DOG) Nie seer 208 1.827 
(GEeays: 2 ee 10% 200 [es Sa IER ee 226 1.994 
Hye M 255 Pee Sy Mamie pr eee 193 1.709 
ELS aces oe omer: M 255 Pees aa WS sche ek 186 1.766 
1B tie se hee atte te M. 255 PA i Mened 0) gee eh Aas 177 1.682 
IPs, ees, ee M. 255 Qe SOc linice ee: ae, 186 1.667 
K M. 260 Oi GAOT Bove g.. 188 1.726 
Ky M. 260 RON De 5 etek 174 1.650 
L M. 223 2. VR He eee 184 1.567 
AVETACES emanates ee 237 2.201 194, 1.740 
Calculated brain weight............. 2.295 1.827 
Observed brain weight differs from 
computed) by =. <7. ys a eee —1.91 —4.65 
per cent per cent 
