SIZE INHERITANCE IN DUCKS Bi 3) 
mean of all their offspring. It seems probable that the mean 
weight of the Rouen stock as here used is rather too small. Ma- 
turity is probably not reached quite as soon by this large breed 
as by the smaller breeds and the very vigorous F, cross-bred birds. 
The mallard stock was obtained from one hundred and twenty- 
five eggs received from a game preserve in New Jersey in the spring 
of 1909. From these eggs sixty-five birds were raised to maturity. 
In 1910 part of this original stock produced one hundred and sixty 
mallards which were raised to maturity. Most of these were 
killed. off and weighed in three lots, October 13, October 22 and 
November 10 (table 3). A comparison of the weights showed that 
TABLE 3 
Weight of pure small race, mallard 
MALES FEMALES 
AGE = 
Grams Grams 
845 819 
854 864 
892 874 
896 855 
910 895 
916 896 
934 970 
944 994 
973 - 1005 
1024 1039 
1064 1048 
APA O MTGE. sea etge re Pee Pte ee ee Sooke ) 1074 
1094 
1096 
1100 
1112 
1115 
1140 
1174 
1180 
1222 
1313 
IMG oe SOC eHaG RO AACN e in OO Oise rane rare ba 1039 935 
