iso charles r. stockard and a. l. johnson 



( 'omparisons of mandibular length avlth other 

 Mandibular Dimensions 



The mandibular lengths of the seventy skulls from different 

 dog breeds show a wide range and a steep slope when rep- 

 resented by lines placed in a sequence for magnitude of this 

 measurement (text-fig. 28). Mandibular length is estimated 

 as a vertical line from the condyle to the level of the anterior 

 end of the symphysis (pi. 35, fig. 4, H-I). These lengths 

 range from 198 mm down to 62 mm, the extremes being as 

 3.2:1. Measurements of other mandibular features show no 

 such wide range. Although the differences in mandibular 

 length in various dog breeds are strongly emphasized, the 

 angles of divergence between the mandibular rami, and the 

 distances between the condyles, may in some cases be more 

 significant for the differentiation of the types. 



2o 



Text-figure 29. Sequence H. Mandibular thickness. Same skull sequence as 

 text-figure 28. 



Mandibular thicknesses, measured in the region of the first 

 molar tooth (pi. 35, fig. 4, E) range from 16 mm down to 5 

 mm or as 3.2 :1 (text-fig. 29). This chart shows a loose general 

 agreement with that for mandibular length but there are wide 

 individual disagreements throughout. 



The measurements of the mandibular premolar regions 

 (text-fig. 30) show somewhat closer agreement with total 

 mandibular lengths, but here again there are strong individual 

 irregularities. The sum totals of the anteroposterior widths 

 of the mandibular premolar teeth (text-fig. 31) are slightly 

 more out of accord with the chart for mandibular lengths 



