228 CHARLES R. STOCKARD AND A. L. JOHNSON 



separately in connection with their hybrid progeny in table 2. 

 Figure 1 in text-figure 56 (p. 239) serves particularly well in 

 familiarizing the reader with the highly contrasted patterns 

 of these pure breed skulls. The solid line in this figure rep- 

 resents the sagittal outline of the dachshund skull from exact 

 measurements. This outline is very long, drawn-out and low. 

 The broken sagittal outline is of the Boston terrier skull and 

 is superimposed on the dachshund as closely as possible. This 

 skull is short and proportionately much higher than that of 

 the dachshund. The two angles drawn below the sagittal 

 outlines, one in solid line and the other in broken line, repre- 

 sent the positions of the anterior alveolar ends of the man- 

 dibles in reference to the anterior tips of the upper jaws. 

 The dachshund mandible lies in a normal position, that is 

 a little posterior to the end of the upper jaw, while the 

 mandible of the Boston terrier lies immediately below the 

 anterior tip of the upper jaw, which indicates malocclusion 

 of the teeth ; that is, instead of normal occlusion of the lower 

 incisors, these incisors are in end to end opposition to those 

 of the upper jaw. 



The differences between these two skulls are shown in 

 a more comprehensive way in plates 36 and 37. Figure 1 in 

 plate 36 illustrates the long, normally proportioned dachshund 

 skull. The upper face, jaws and teeth are typical of the 

 standard typed dog skull. The dental occlusion is perfect, 

 with the lower incisors fitting in closely behind the upper 

 incisors and the lower canine tooth locking into the interval 

 between the third upper incisor and the upper canine. This 

 arrangement is responsible for the efficient, sharp and tearing 



PLATE 36 



EXPCANATION OF FIGURES 



Skulls of the cross between the dachshund and Boston terrier showing con- 

 trasting characteristics of the pure breeds and the resulting conditions in the 

 first and second generation hybrids. 



1 Dachshund 84$. 4 F 3 294$. 



2 Boston terrier 76 $. 5 F 2 296 $. 



3 F, 130$. 6 F 2 295$. 



