GENETIC TYPE AND THE ENDOCRINES 153 



original stem, and the presence in the dog company of the 

 perfectly formed wolf-like skull of our standard control 

 German shepherd dog is very fortunate indeed. 



Three different aspects of the shepherd skull photographed 

 with comparable views of the English bulldog skull are shown 

 in plate 50 (p. 275). If these two skulls were found as fossils, 

 a paleontologist would hesitate to class them as belonging 

 to any one family of Carnivora. The shepherd skull is in 

 all aspects closely reminiscent of the skull of the wolf. 



A check of the literature on the dog breeds did not bring 

 to light any exact information on the growth of the skull 

 in the dog, and no comparative measurements showing the 

 contrasts among the various dimensions found in the skulls 

 of different breeds are available. The fixed points from which 

 growths take place in order to give the characteristic skull 

 forms for the dog have not been determined. We were forced, 

 therefore, to plot the numerous dimensions of these skulls 

 in order to determine which were significantly important in 

 the comparison of types. Linear measurements of a complex 

 object such as this are not alone sufficient, and indices have 

 been determined to facilitate more complete comparisons. 

 The measurements in themselves are not difficult to make, 

 yet it is often hard to locate the measurement between two 

 points or the index of a region which would be consistently 

 and significantly indicative of an inclination toward one or 

 another type. It was thus decided to map a number of points 

 on the skull and record a complete series of measurements 

 between certain of these, the expectation being that such 

 measurements derived from a sample group of skulls from 

 different breeds might be compared graphically so as to de- 

 termine the lines of type differences and agreements. 



Plate 35 illustrates the points and lines which were decided 

 upon for making these measurements. Figure 1 shows the 

 two sagittal measurements made from the dorsal aspect of 

 the skull: cranial length, the straight distance between the 

 supraoccipital spine and the nasion, line H-I in the figure; 



