GENETIC TYPE AND THE ENDOCRINES 269 



the other two showing greater width than length. Thus the 

 skull types of these breeds are extremely divergent for the 

 total skull index. 



Three F l hybrid skulls show total skull indices from 70 

 to 75, the lowest being only 3 units above the dachshund 

 group while the highest falls 19 units below the index for 

 the longest French bulldog skull. For this feature, therefore, 

 the Fj skull is very close to that of the dachshund. 



Among the eleven F 2 skulls, the total skull indices range 

 from 67 to 82. The lowest of these indices reach those of 

 the dachshund, while the highest is 12 units below the lowest 

 skull index for the French bulldog and 29 points below the 

 highest. When crossed with the dachshund typed skull, this 

 character is equally as recessive in composition in the skull 

 of the French bulldog as it is in the Boston terrier skull. 



The palatal index, also a highly different character in these 

 two types of skulls, is shown in the bottom chart in this 

 figure, and its record is closely the same as that for the 

 total skull index. Again the hybrid generations tend to ap- 

 proach more nearly the largely dominant dachshund pattern. 



Text-figure 62 records the snout index and the upper facial 

 index for the same skulls as are represented in the previous 

 figure. The top chart shows the snout index to be the most 

 highly contrasted feature in the skulls of the dachshund and 

 the French bulldog, just as was found for the skulls of the 

 Boston terrier and dachshund. The upper facial index is 

 again represented as derived from a method of calculation 

 the reverse to that for the other indices, and thus the long- 

 face is indicated by the large rather than the small index 

 value. 



The snout indices for the F! skulls are very far from 

 those for the French bulldog but comparatively close to 

 those for the dachshund. The F 2 indices vary; the lowest 

 is down to those for the dachshund, but the highest is only 

 about half as much as the French bulldog values. 



