98 CHARLES R. STOCKARD 



largely dominant over hoimd typed bone. We have seen that 

 the Fj bassethound-bulldogs have legs as short as the pure 

 bassethound. The reason for this is that a single factor for 

 achondroplasia, acting in association with the constitution 

 for bulldog bone, induces a greater or more complete achon- 

 droplasic effect than is the case for other types of bone. 

 Bulldog bone is in type short and stocky, as contrasted, for 

 example, with the long and slender type of Saluki bone. We 

 have much evidence for the statement that short and stocky 

 bone is more completely affected in the presence of the achon- 

 droplasia leg gene than is the long, slender type of bone. 

 After further consideration of the F 2 bassethound-bulldog 

 legs we shall discuss the bone types in more detail. 



Figures 6-9 of plate 19 show four litter mate F 2 basset- 

 hound-bulldogs, two of which have achondroplasia legs and 

 two normal legs. Figure 7 has typical bulldog legs as in the 

 grandfather (fig. 1). The skeleton of this animal, 916 6 , is 

 shown in plates 20 and 21 (figs. 8), and from both aspects 

 the leg is seen to be closely similar to that of the bulldog, 

 shown as figure 1 in these two plates. Figure 8 in plate 19 

 si lows a sister, 918 9 , which also has long legs, but of an 

 entirely different type. These legs are those of a foxhound, 

 almost as long and slender as the legs of the German shepherd. 

 The bone types of the bulldog and hound parent stocks are 

 thus again segregated out among these F 2 s. 



Figures 6 and 9 of plate 19 show animals with achondro- 

 plasia legs, and we have diagnosed animal 917 $ (fig. 6) from 

 both life and a study of the skeleton as short ss for achondro- 

 plasia on hound typed bone. The skeleton of this dog is 

 shown in plates 20 and 21 (figs. 5). The short legged animal 

 in figure 9 of plate 19 gives all evidence for bulldog typed 

 bone and is diagnosed from life and a study of its skeleton 

 as heterozygous for short achondroplasia legs on bulldog bone. 

 The skeleton of this animal, 919 9 , is shown as figure 7 in 

 plates 20 and 21 and should be compared with the two F : 

 skeletons in the middle row of both plates, since we have 

 interpreted the leg conditions in the three as being the same. 



