SKELETAL DIMENSIONS 



43 



The measurements made upon the 2 three-quarter-blood lops (0*492 

 and 9 504) indicate that in their production, as in that of half-lops, the 

 inheritance of skeletal dimensions is blending. 



It would be premature to conclude that such is the case in all mammals. 

 Farrabee (105) has shown that in man hypophylangia (2-jointed fingers and 

 toes) is associated with an abnormal shortness of the arms, legs, and trunk. 

 It would seem that all the skeletal parts are abnormally shortened. In- 

 heritance in this case is clearly not blending, but alternative. Some dis- 

 continuous alteration has evidently occurred in the growth-character of 

 cells that form the skeleton, just as in the activities of the follicle cells in 

 long-haired mammals (see Castle and Forbes, : 06). It would be of inter- 

 est to know whether such is the case also in bantam fowls and Shetland 

 ponies. 



TABLE 30. Bone measurements of rabbits. 



Aside, however, from such unusual cases, it seems probable that skel- 

 etal dimensions, and so proportions of skeletal parts, behave in general 

 as blending characters. The linear dimensions of the skeletal parts of 

 an individual approximate closely the mid-parental dimensions. 



Volume and weight magnitudes, however, follow a different law, which 

 has not yet been clearly made out. It is plain that they are less than the 

 mid-parental magnitude. (See Part II.) 



