GENETIC TYPE AND THE ENDOCRINES 309 



among the ten pure bulldogs, but is more than 50 units below 

 the three highest. 



The snout index again represents a complex of several 

 characters which are influenced in their expression by a num- 

 ber of different genetic factors. The normal length of snout 

 growth tends to dominate in a general way the short bulldog 

 muzzle. 



The relation of width to length of the palate has been ex- 

 pressed as the palatal index and is shown in text-figure 67. 

 In the same figure, the mandibular index is represented by 

 the lower chart. A close comparison of these two indices is 

 particularly important since the first one may be taken as 

 the most representative for the upper jaw while the man- 

 dibular index expresses, of course, the width to length pro- 

 portion for the lower jaw. The mandible in the bulldog skull 

 is less shortened than is the palatal or upper jaw region, and 

 the charts show the differences for palatal index between the 

 bulldog and the bassethound to be much greater than for 

 mandibular index. 



The bulldog skulls are fairly uniform in their palatal in- 

 dices but even more so in their mandibular indices. In both 

 these indices the F l hybrids are much nearer to the basset- 

 hound skull pattern than to that of the bulldog. Three F t 

 palatal indices are shown to be close to the bassethound, and 

 the nine Fj mandibular indices are also more bassethound-like. 



The twenty-one F2 bassethound-bulldog skulls measured 

 for palatal index range from 74, which is about the same 

 as the highest bassethound index, to 96, which is 14 units 

 below the lowest bulldog index of 110. The bony palate is 

 wider than it is long in all eight bulldog skulls, but in not 

 one of the twenty-one F 2 skulls is this the case. The majority 

 of the F2 skulls are within the F l range and in general 

 approach the bassethound skull more nearly than they do 

 that of the bulldog. 



The range in mandibular index is shown in the lower chart 

 of text-figure 67. Not only do the bassethound and bulldog 



