GENETIC TYPE AND THE ENDOCRINES 



165 



The interorbital distance (pi. 35, fig. 1, D), which is to 

 some extent involved in the anterior cranial region through 

 the influence of the frontal bone on this measurement, was 

 plotted for the skulls in the same cranial width sequence. 

 A comparison of text-figures 13 and 11 shows no smooth 

 accord between cranial width and interorbital width and there 

 is a much greater range in dimensions in these interorbital 

 widths than in the other two cranial width measurements. 

 Interorbital widths range from 57 mm down to only 22 mm, 

 the extremes differing as 2.6:1. 



So 



Zo 



/o 



Text-figure 13. Sequence B. Interorbital width. Same skull sequence as text- 

 figure 11. 



It is somewhat surprising to find that there is such wide 

 variation in the interrelations of these three measurements 

 among the seventy skulls of the different dog breeds. This 

 fact indicates that cranial shapes of different dog breeds are 

 considerably contrasted on the basis of the widths at dif- 

 ferent regions. The differences in cranial lengths have not 

 thus far entered into the picture, though we shall later see 

 that such differences are even more important than differences 

 in width. 



It is difficult to determine from text-figures 12 and 13 

 whether there is any definite accord between least frontal 

 widths and interorbital widths. For this reason the measure- 



