296 GROWTH OF PARTS AND ORGANS 



(1) For the male 



Body weight = 10°°°~ ''''■ 'x^oo-l^^'^- '-xiooxo.ooii+iesoo) _-^g ^^^^ 



_ 1 qO.0000629 (Bd. Z.X99. 6+16500) _ -i o 



(2) For the female 



Body weight = 10°°~9 (B.i. i.xioo+mi. lxiooxo.oo4+i6500) _ ^g ^^^^ 



_ -|q0.000C629 (Srf. Z.X100.1+I6500) _ -i o 



Formulas (54) (55) were used for table 187. 



Tail Length on Body Length, Norway (Hatai, ms '14) 



(1) For the male 



Tail length = 0.824 Bd. I + 39.1 {log. Bd. I.) - 92.6 (50) 



(2) For the female. 



Tail length = 0.824 Bd. I. + 43.1 log {Bd. I.) - 98.4 (57) 

 Formulas (56) (57) were used for table 187. 



Brain Weight on Body Weight, Norway (Donaldson and Hatai, '11) 



Brain weight {sexes combined) 



= 0.825 log {Bd. wt. - 4) + 0.233 (58) 



This formula applies only to rats 5 grams or more in body 

 weight. To obtain the weights for the male the values given 

 by the formula are increased by 1 per cent, and to obtain the 

 weights for the female, they are decreased by 1 per cent. 



Formula (58) with corrections mentioned above was used for 

 table 187. 



Crajjial Capacity on Body Weight, Norway (Donaldson, '12) 



Cranial capacity in cc. {sexes combined) = 



0.00105 Bd. wt. + 0.548 log Bd. wt. + 0.476 (59) 



[80 < Bd. wt. < 380] 



