GENETIC TYPE AND THE ENDOCRINES 61 



The backcross hybrids exhibit the hair texture and coat 

 pattern of the shepherd, as seen in plate 5. Some of these 

 are also quite shepherd-like in behavior. Only one among 

 the fairly large number of animals, however, had perfectly 

 erect, typically shepherd typed ears although two others 

 showed ears which were almost erect. The backcross animal 

 with erect ears is shown in plate 5 (fig. 4). The head and 

 body of this dog would be mistaken for pure shepherd and 

 the tail is also shepherd-like, but strangely enough the body 

 is carried upon achondroplasic bassethound legs. When the 

 reader places his hand over the photograph so as to cover 

 the legs of this dog, its shepherd type then becomes more 

 strongly pronounced; when the hand is removed the strange 

 appearance due to the short legs is exaggerated. 



The erect ear of the shepherd is a complex character de- 

 pending in its inheritance upon multiple factors, of which 

 most are recessive in expression, as is illustrated by its rare 

 appearance in these backcross hybrids. As is well known, 

 the breeders of pure shepherd dogs frequently have difficulty 

 in maintaining strongly erect ears in their stocks. This is 

 no doubt due to its complex and recessive nature. 



Summarizing our present point of interest in the backcross 

 of the F a shepherd-bassethound with the shepherd parent, 

 it is clear that the normal leg of the shepherd is recessive 

 to achondroplasia on a single factor basis. 



The F! basscthoinid-shepherd backcrossed ivith the basset- 

 hound. The F! bassethound-shepherd was also crossed back 

 on the bassethound parent stock. On the basis of the leg 

 conditions in the F 2 generation as already discussed, and the 

 results of the backcross on the shepherd given in the preceding 

 section, we should expect the bassethound backcross to pro- 

 duce only achondroplasic short legs. Furthermore, we should 

 expect these short legs to be of two different classes. Since 

 the pure bassethound is homozygous for achondroplasia of 

 the leg we may represent the genes chiefly concerned as ss, 

 and since the F t shepherd-bassethound is heterozygous or 

 hybrid for this condition of the leg its genie composition 



