Sept. i8, 1916 



Dwarf Eggs 



991 



(2) length, and (3) breadth. In order to determine whether or not 

 these apparent differences may be considered significant, the differences 

 with their probable errors and the ratio of each difference to its probable 

 error are given in Table VI. 



Table VI. — Difference between the coefficients of variation in the size characters, together 

 with the probable error of difference and the ratio of each difference to its probable error, 

 for normal eggs and for each class of egg-shaped dwarf eggs 



From 430 eggs laid by a flock of Barred Plymouth Rock pullets in a single day. 



From Table VI it appears that the order of variability of the characters 

 is probably significant — that is, in both normal and dwarf eggs the size 

 characters may be arranged in the order of their variability as egg weight, 

 length, and breadth. The only case where the difference is less than 

 three times its probable error is between length and breath in "cock 

 eggs" with small yolks. In this case the deviation might have been due 

 to errors of sampling. 



In normal eggs it has been shown by Curtis (4) that the weight of the 

 whole egg is less variable than the weight of any part (yolk, albumen, or 

 shell). Of the three parts the shell is the most and the yolk the least 

 variable. The coefficients calculated for 16 dwarf eggs with small 

 yolks do not show the same relative variability of the parts. In these 

 eggs the weight of albumen was less variable than the weight of the 

 whole egg, and the yolk weight instead of being the most constant of the 

 three parts was the most variable. The number of eggs, however, is so 

 small that the probable error of sampling is large. Table VII shows that 

 when the coefficients of variation of the egg parts are arranged in the 

 order of their value, the differences between the two of nearest value is in 

 no case equal to three times the probable error of difference. It is, 

 however, probable that yolk weight is more variable compared to the 

 weight of the other parts and to the whole egg in small-yolked dwarf 

 than in normal eggs. 

 55853°— 16 2 



