52 CHARLES R. STOCKARD 



for long is paired with that for short as in the homozygous 

 state with both allels for short. There is also another possible 

 reason why the F! hybrid is not so short legged as the basset- 

 hound. In general, the leg bones of hounds are not so slender 

 and long as those of the German shepherd dog and there is 

 the possibility that the shepherd type of bone is more domi- 

 nant in the Fj and not so extremely shortened by achondro- 

 plasia. In other words, the constitutional type of the bone 

 itself may modify the expression of the achondroplasic con- 

 dition. Both the above possible explanations for the incom- 

 plete shortening of the F! leg have been analyzed by studying 

 the later generations and backcrosses of this combination as 

 well as by testing the chondrodystrophic response in the bone 

 types of other breeds. 



Before considering leg inheritance in the further genera- 

 tions of the shepherd-bassethound cross we may mention in 

 general some of the other qualities and characters of these F x 

 hybrids. Without exception they show the coat of the shep- 

 herd dog, the hair being thicker than in the bassethound and 

 moderately long, with a color pattern closely similar to that 

 of the shepherd. The ears are of medium size, much smaller 

 than those of the hound, but are pendulous or hanging as in 

 the bassethound and are never held erect. The tail is carried 

 in a shepherd-like manner. The F x hybrids are more active 

 than the bassethound, but when running free to hunt, or 

 when being led on a leash, drop their heads down and scent 

 with the nose to the ground just as does the bassethound 

 parent. The voice and barking reactions are not completely 

 hound-like yet are fuller and somewhat different from the 

 shepherd. They are shepherd coated and colored but are 

 short legged with hanging ears, and physically are hound-like 

 rather than shepherd. These hybrids are large, heavy and 

 very vigorous. Their glands of internal secretion, as we shall 

 show in a subsequent chapter, are quite normal, the only 

 peculiarity being that their thyroid glands are proportionally 

 quite large. The reproductive reactions in these F! basset- 

 hound-shepherds are normal and they produce from five to 



