288 CHARLES R. STOCKARD AND A. L. JOHNSON 



These general considerations of the structural character- 

 istics and developmental modifications in the bulldog* type 

 prepare us for an understanding' of the genetic and environ- 

 mental influences which are involved in the origin of such 

 expressions. A genetic analysis of the conditions has been 

 attempted by employing in the experimental studies the 

 grotesquely featured English bulldog with its extremely 

 achondroplasic skull, and crossing members of this breed with 

 breeds having a normal wild typed hound skull. 



The Contrasted Skulls of the English Bulldog and the 

 German Shepherd 



Only a limited test of the genetic reactions of the factors 

 involved in the production of the full typed bulldog skull 

 when contrasted with the normal standard shepherd skull 

 was made, this being due to the fact that both breeds are 

 not dependable as breeders nor sufficiently prolific to be well 

 suited to such experiments. The bulldog-bassethound cross 

 proved far more favorable, since the bassethound is a steady 

 and reliable breeder and genetic tests could be readily made 

 through its offspring in all necessary directions. Neverthe- 

 less, certain points of value were derived from the bulldog- 

 shepherd cross and these will be given briefly. 



A registered German shepherd, "Else" 118 9, who was of 

 carefully pedigreed lines with a perfect typed head, was 

 bred to "Lome's Latest," A.K.C. 651313, a bulldog of cham- 

 pion stock witli a well expressed bulldog head. Fortunately, 

 lliis bulldog was a remarkably good sire and was used in 

 these experiments a number of times. He lived to be only 

 slightly more than 5 years of age and died suddenly while 

 out walking with his master. Within a few hours after death 

 this animal was sent to our laboratory for autopsy and the 

 fresh endocrine glands were obtained for study. His skeleton 

 was also prepared and mounted to serve as a permanent 

 record. 



