J. W. Jenkinson 
Fig. 1 is the corresponding frequency polygon. 
(201 
151 
■ 9o -80 -70 -60 -50 
+ 10 *20 +30 t-tO + 30 +60 +70 +80 -+90 
Fig. 1. First Furrow and Sagittal Plane. 
It will be seen that there is a very decided tendency for the two planes to 
coincide. Still all deviations are possible and all occur, and occur pretty equally 
in either direction, for the polygon is fairly symmetrical. 
This tendency towards coincidence might not unnaturally lead to the supposi- 
tion that there is a causal connection between the two. The correlation table 
(Table II.) quite negatives this idea. 
The table, which was constructed by taking in each egg the angle between the 
plane of symmetry and the first furrow and that between the plane of symmetry 
and the sagittal plane, shows clearly how small the correlation is ; it works out 
at p = "138 + '031. Figs. 2 and 3, regression schemes constructed from the 
correlation table, emphasize the point. It will be noticed, however, that in 
Fig. 2 the regression line is rather sharply bent away froin the horizontal on the 
