358 CHARLES E. STOCKABD AND A. L. JOHNSON 



crosses between the flat faced and the long muzzled breeds 

 furnish evidence of importance in the analysis of the nature 

 of these facial patterns. 



Structural disharmonies closely similar to those under dis- 

 cussion are very common in the faces of human beings. There 

 are faces of narrow, wedged, sharp type and wide flat type 

 with very distinct differences in patterns for the two jaws, 

 and a careful observer may commonly see the hybrid com- 

 binations of these jaw patterns. Orthodontists are constantly 

 attempting to correct the dental malocclusion of children with 

 the overshot condition or maxillary prognathism, and people 

 are continually losing their teeth because of malocclusion due 

 to the undershot prognathous mandible. The overshot prog- 

 nathous upper jaw is very common and very disfiguring, and 

 the undershot jaw associated with a somewhat flat upper face 

 is met with in every community. There is little doubt that 

 these disharmonies can be registered among those ills resulting 

 from type and racial hybridization. 



We shall next consider the final and most striking breed 

 cross that has been made in our efforts to understand the 

 transmission and development of these strange and highly 

 modified facial structures. 



THE CROSS BETWEEN THE PEKINGESE AND THE SALTJKI 



The inheritance and development of the achondroplasic 

 flat faced head of the Pekingese was finally tested by crossing 

 this dog with the extremely slender and long faced Saluki 

 greyhound. The cross between these two widely different 

 breeds is most difficult to accomplish, and we have not yet 

 secured a large number of the hybrids. The characters under 

 study, however, are so highly contrasted that this cross offers 

 important results even in its present uncompleted state. 



In a previous section we discussed the simple dominance 

 of the short achondroplasic leg of the Pekingese over the 

 long, slender Saluki leg. The genetics of leg length will be 

 clearly seen by referring again to plate 34 (p. 138). It is well 



