260 CHARLES R. STOCKARD AND A. L. JOHNSON 



to avoid confusing the living F x hybrids of these two crosses. 

 They not only resemble one another physically, but behave 

 very much alike. The French bulldog-dachshund F! is the 

 somewhat stockier and slightly heavier of the two. Its head 

 is far from the French bulldog type, and is shorter and with 

 a more pronounced "stop" than that of the dachshund. The 

 ten FjS used in our experiments were all closely alike; five 

 were used for adult comparisons and five were examined 

 closely as young puppies. The matings among these F l 

 hybrids produced four litters of F 2 animals, numbering six, 

 seven, five and three puppies. These litter sizes are a little 

 above the expectation for French bulldog whelpings but are 

 easily within the fecundity expectations for the dachshund. 

 The F2 generation of hybrids from this cross contains 

 individuals of extremely varied form and type, just as was 

 the case among the Boston terrier-dachshund F 2 progeny. 

 Among the twenty-one F2 specimens, a large majority were, 

 as would be expected, short legged. A number of them showed 

 prognathism of the lower jaw because of the abnormal short- 

 ness of the maxilla. In other eases there was opposition of 

 the incisors, yet normal occlusion of these teeth was also 

 presented. Sixteen of them had long straight tails as in the 

 dachshund grandparent, one showed a long tail bent at several 

 places, two had tails slightly shortened and bent and two 

 possessed the typical short, twisted "screw-tail" of the French 

 bulldog stock. Plate 46 (figs. 5-8) shows four litter mate 

 F 2 French bulldog-dachshunds. It would be difficult to find 

 four dogs of about the same body size differing more widely 

 in type than do this male dog and his three litter sisters. 

 The bitch in figure 5 has a typical dachshund head, body 



PLATE 46 



EXPLANATION OF FIGURES 



Cross between the contrasted dachshund and French bulldog showing inheritance 

 of skull characteristics and other physical features in the first and second 

 generation hybrids. 



1 Dachshund. 5-8 F 2 hybrids. 



2 French bulldog. 5 668$. 7 666^. 

 3-4 F, hybrids. 6 667 $. 8 669 $. 



