WEIGHT 



39 



in excess of the mid-parental (table 27), but since he shows a less per- 

 centage of bone to total body-weight than either parent it is probable 

 that the excess is due in part at least to some temporary condition (fat- 

 ness). If he showed a mid-parental percentage 1 of bone to body-weight, 

 and this would possibly be the case if all 3 rabbits had been in like con- 

 dition, as regards fatness, then his weight should be something less than 

 the mid-parental weight, or about 3,326 grams, instead of the mid-parental 

 weight (3,800) or the observed maximum weight (3,930). But in the 

 absence of more extensive observations, we can not be certain that the 

 percentage ratio of bone to body-weight is a mid-percentage. The ques- 

 tion must remain an open one until further data can be accumulated. 



TABLE 27. Relation between bone-weights and total body-weight in the 



rabbit J 248 and in his parents. 



As regards bone-size, however, we can reach more satisfactory conclu- 

 sions, for this character is unaffected by temporary conditions of the flesh. 

 In table 29 are recorded bone measurements of this family of rabbits, 

 which show the measurements of the son ( cf 248) to be close to the mid- 

 parental as regards both absolute measurements and proportions of parts. 



In table 28 are recorded observations upon the weight and volume of 

 certain bones of these same rabbits. Both in weight and in volume the 

 bones of the son are less than the mid-parental. This is what we should 

 expect if the bones of the son correspond with the mid-parental hi linear 

 dimensions and in the proportions of parts; for linear dimensions should 

 be to each other about as the cube roots of the volumes and weights (pro- 

 vided the specific gravity is alike in all three cases). 2 On this hypothesis 

 "expected weights" and "expected volumes" have been calculated for 

 the son, and these are entered in table 28 in a parallel column, along with 

 the observed weights and volumes. It will be noticed that the "expected" 

 uniformly exceed the observed weights and volumes. The expected, to 

 be sure, is less than the mid-parental, but the observed is still less. As 

 regards the total weights of the parts observed, a graphic presentation is 

 made in fig. 4 of the relation of mid-parental to expected and observed. 

 The expected falls below the mid-parental by a certain amount, but the 



1 The percentages given are based upon the combined weights of particular bones, not of all the 

 bones of the body. 



2 A comparison of the weights and volumes of corresponding bones in table 28 indicates that the 

 specific gravity of the bones of the son ((^248) was slightly less than that of either parent, viz, 

 about 1.19 for the son, 1.20 for the mother, and 1.26 for the father. 



