20 40 60 



100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420.440 460 480 



Fig. 8 Graphs showing the increase in the weight of the body with age for 

 males belonging in the seventh to the fifteeth generations of the two series of 

 inbreds (data in table 11 and in table 12). 



20 40 60 



l60 120 140 160 i80'266 220 240 260 280 300 320 340' 360 380 400 420 4iO 460 480 



Fig. 9 Graphs showing the increase in the weight of the body with age for 

 females belonging in the seventh to the fifteenth generations of the two series 

 of inbreds (data in table 11 and in table 12). 



26 



