266 CHARLES R. STOCKARD AND A. L. JOHNSON 



The skull indices and proportions for the pure parent breeds 

 and the averages for the same features in the F x and F 2 

 generations are given in table 3. The average indices for the 

 three Fj hybrid specimens are very similar to the averages 

 for the eleven F 2 skulls, although the standard deviations 

 for the F 2 group are, of course, much greater than for the 

 F 2 s. The deviations for some of the F 2 features are several 

 times larger than they are for the same characters in the Fj. 

 Again the average indices for the hybrid generations fall 

 between the indices of the two pure stocks. The range in 

 expression of the skull characters in the F 2 hybrids towards 

 one or the other parent type is not evident from this table. 

 In order to show this range, charts representing the indices 

 for the individual skulls have been arranged. 



Text-figure 61 presents charts representing the cranial 

 index, total skull index and palatal index for the individual 

 skulls of the two pure stocks and the hybrid generations. 



The cranial index in the two pure breeds is not very different, 

 although it is, on the whole, slightly lower in the dachshund. 

 Considering the very elongated total skull of the dachshund, 

 its cranial index is really quite high and approaches the bull- 

 dog index more closely than is usual for long skulls, such 

 as those of the bassethound and foxhound. 



The cranial indices in the Fi skulls are well below those 

 for the French bulldog and are actually lower than the index 

 in three of the four pure dachshund skulls. 



Eleven F 2 skulls show the full expectation for range in 

 the cranial index. Four of these indices are lower than that 

 of the lowest dachshund and two are as high as the highest 

 cranial indices for the French bulldog. The F L > indices also 

 range well above and below two of the three F x s. The average 

 of the Fo indices, as shown in table 3, completely conceals 

 this wide range, but does indicate the tendency of the hybrid 

 skulls to fall between the two parent types in this character- 

 istic. 



