GENETIC TYPE AXD THE EXDOCIUNES 215 



at the top of the chart. The St. Bernard skull is very large, 

 the great Dane is slightly smaller, and the dachshund skull 

 only about half the size of either of the first two. In spite 

 of this discrepancy in size, the outlines of the three skulls 

 are on an almost identical pattern. 



The columns in this figure represent the averages for seven 

 St. Bernard, four Dane and four dachshund skulls. The 

 St. Bernard skulls, as indicated by the blank spaces at the 

 top of the black columns, are more variable for indices and 

 dimensions than the other two. The upper facial index and 

 the breadth-height index in the skull of this dog are very 

 variable although the averages for these indices are quite 

 similar in the three breeds. The skull variations in the St. 

 Bernard are very probably associated with differing degrees 

 of the acromegalic reaction in the skulls of this breed. 



The dachshund falls well below the other two skulls for 

 zygomatic width and orbital width, but these differences are 

 due solely to the smaller size of the skull and are in no sense 

 indicative of deviations in type. In general the twenty sets 

 of columns shown in this chart indicate that there is a 

 surprisingly close uniformity in type among the skulls from 

 these three very different dog breeds. 



The skulls represented in text-figure 53 are almost entirely 

 different in pattern from those represented in the two previous 

 figures. At the top of the chart, outlines of relative dimen- 

 sions arc given for the three skulls. These three outlines are 

 just as closely uniform in their patterns as are those of the 

 standard typed skulls in text-figure 51. As indicated in table 1, 

 the characters were measured from the skulls of nine English 

 bulldogs, four French bulldogs and five Boston terriers. The 

 bulldog typed skulls are shown by this figure to be more 

 variable for indices and dimensions than are those of the 

 two previous groups, and in most of the characters indicated 

 the English bulldog skull is more variable than those of 

 the Boston terrier or the French bulldog. In spite of this 

 variability, the average indices for the three skulls are re- 

 markably close together for all features indicated. In zygo- 



