92 CHARLES R. STOCKARD 



a male and two females, were whelped from this mating-. 

 The three hybrids lived to be adults and were all closely 

 similar in their physical characters as well as their be- 

 haviors. They were sturdy, stocky, handsome animals re- 

 sembling in general the mastiff-like dog known as the German 

 boxer. One of these hybrid females is shown as figure 4. The 

 physical characters of both the shepherd and the bulldog 

 are almost completely lost in this hybrid, and persons familiar 

 with dog breeds fail to guess the origin of the bulldog-shepherd 

 Fj more frequently than that of any other cross or breed in our 

 kennels. The legs of this bulldog-shepherd bitch are perfectly 

 straight and well set, resembling more those of the shepherd 

 than the bulldog. Certainly there is no dominant symptom 

 of achondroplasia to be found in the legs of these hybrids, 

 and in the light of the foregoing discussion of the genetics 

 of this condition, we must presume that the bulldog does 

 not carry factors for this type of leg modification. Further, 

 in this cross at least, there is no spreading or generalizing 

 of the achondroplasia in the axial skeleton of the bulldog. 

 On the basis of this test our diagnosis of the English bulldog's 

 appearance as due to localized achondroplasic growth in the 

 skull and axial skeleton without modified growth in long 

 bones of the extremities, is very much strengthened. 



We must make one qualification in the statement that chon- 

 drodystrophy in the bulldog is strictly confined to the axial 

 skeleton. For this reason we have emphasized its absence 

 from the long bones of the leg rather than from the entire 

 appendicular skeleton. The cartilage growth in both the pec- 

 toral and pelvic girdles is affected. The labial cartilages of 

 the glenoid fossa on the scapula and of the acetabular fossa 

 of the pelvic bones are somewhat deficient and thin, causing 

 the fossae to be abnormally shallow. In such cases the heads 

 of the humerus and the femur may be dislocated from the 

 shallow sockets. This occurrence is not rare in the bulldog 

 but as a rule the sockets are sufficiently deep to prevent easy 

 luxation. In cases of dislocation of either one or both shoulder 

 joints, one or both hip joints, or all four joints, the condition 



