II. SIZE OF THE BODY AND ORGANS 103 



indication of the influence of unfavorable conditions, and tin- 

 weights for the captive Grays are similar to those for the 

 wild strain. Thus, there is no modification in the weights 

 bringing these down to those of the Albino. On the whole, 

 captivity and unfavorable conditions appear to have pro- 

 duced less effect on the testes than on any other organ studied. 

 In the case of the ovaries, the weights remain as high or 

 even a little higher than in the wild strain, but in contrast 

 to the testes the ovaries do seem to respond to the unfavor- 

 able conditions with lower values at G 5 and G 7 . The failure 

 of the gonads to change in weight during the first ten genera- 

 tions of captivity was unexpected, in view of the much lower 

 weight values for the gonads shown by the Albinos. 



Parts of the skeleton (series -2), table 25, chart 22 



Length, weight, and percentage of water. Femur. As 

 noted in the previous consideration of the data in series 2, the 

 various parts and bones examined for length, weight, and 

 percentage of water agree in their general behavior with one 

 another. For this reason it was deemed sufficient to note in 

 detail the results for the femur. Between G 4 and GI O there 

 is, in the femur, no progressive change in length, weight, or 

 percentage of water. The unfavorable conditions are marked 

 by low values in each of these characters from G 5 to G 7 . We 

 have no reference tabled for these characters in the wild 

 strain, but, as the results stand, the femur in the captive Gray 

 is distinctly heavier and has about the same length and a 

 slightly greater percentage of water than in the Albino. 

 Under unfavorable conditions, the femur becomes more 

 slender (i.e., the weight is. more reduced than the length), the 

 cavity is diminished, and the percentage of water ilcm -a -'<!. 

 All that can be said in a general way is that there is no pro- 

 gressive change in these characters between G 4 and G, () . The 

 striking result in this case is the great susceptibility of the 

 osseous system as represented by the femur to unfavor- 

 able conditions, to which it responds with marked reductions 

 in weight and in percentage of water. 



