138 CHARLES R. STOCKAED 



puppies, a male and female, both of which lived to produce 

 several litters of F 2 hybrids. 



Plate 34 illustrates the two parent types (figs. 1-4), and 

 an Fj tan male (fig. 5) and his black and tan sister (fig. 6). 

 The extremities in both F x s have fallen far short of the 

 Saluki and are typically heterozygous achondroplasic legs. 

 A single litter of five F 2 animals is shown in figures 7 to 11. 

 It is quite obvious from even these small photographs that 

 here again we have a Mendelian segregation of the single 

 factor dominant short leg character. The F 2 animal in figure 

 7 has straight long legs though certainly not of slender Saluki 

 bone pattern. The second animal (fig. 8) has intermediate 

 length legs like the Ft parents. The next two (figs. 9-10) 

 show legs of questionable shortness ; they seem shorter than 

 the FjS, but this may be due to the action of the heterozygous 

 condition on Pekingese bone type, just as the long legged 

 bitch in figure 7 is not a tall dog and certainly does not 

 possess Saluki typed bone. The fifth member of this litter 

 (fig. 11) has unquestionably pure completely short extremi- 

 ties. It is very short with knocked-in wrists closely resembling 

 the Pekingese grandparent. Two other litters of F._, animals 

 bear out the supposition that the achondroplasic short ex- 

 tremities of the Asiatic Pekingese are due to a genetic back- 

 ground which, on crossing with normal long legged animals, 

 reacts in exactly the same way as does the achondroplasic 

 extremities in European breed crosses. 



PLATE 34 



EXPLANATION OF FIGURES 



Cross between the Pekingese and Saluki to determine whether the short leg 

 character in the Pekingese (an Asiatic breed) reacts in its inheritance in the 

 same manner as in the bassethonnd and dachshund (European breeds). 



1 Pekingese 1119$, Saluki 835$. 7-11 One litter of five F 2 s. 



