No. 527] 



SKIN PIGMENTATION IN MAN 



i;r.i 



pectation is that all of its offspring shall be brunet. 

 This condition is apparently not realized even in the 29 

 families that yield no blonds. Only in seven cases are 

 both [grand] parents of the brown parent "brunet," 

 but there is no evidence that they were not simplex. At 

 any rate, in all these seven cases some "intermediate" 

 offspring were produced. 



{g) Comparisons. — The relations of the foregoing 

 facts are better brought out by the compact table where 

 the results of the various matings can be compared. 



TABLE VII 



The Number and Distribution of the Offspring of Various Matings 



BlondXbrunet 403 I 193 88 | 122 1 47.9 21.8 30.3 



Int.Tnu.liateXmtermediate . 591 128 ' 403 ■ 60 21.8 68.5 I 9.7 



lntorn.cliateXl.runet 307 73 129 1 105 23.8 42.0 34.2 



BrunetXbrunet ! 173 42 30 101 I 24.3 17.3 58.4 



Totals | 2,394 I 1,129 I 843 | 423 | 



Considering alone the proportions of blonds in the 

 families of the various matings, some striking figures are 

 obtained. Three classes appear: 



I. Class comprising about 90 per cent, blonds ap- 

 proaching 100 per cent.— blond X blond (91.4 per cent.). 



II. Classes in which the blonds constitute approxi- 

 mately 50 per cent. — blond X intermediate (54.9 per 

 cent.), blond X brunet (48 per cent.). 



III. Classes in which the blonds constitute approxi- 

 mately 25 per cent.— brunet X brunet (24.3 per cent.), 

 brunet X intermediate (23.8 per cent.), intermediate X 

 intermediate (21.8 per cent.). 



In the first class neither parent shows skin pigment; 

 in the second class one parent only shows such pigment ; 

 in the third class both parents show skin pigment. The 

 proportions of blonds in the first class are those ex- 

 pected from Mendelian crosses of R X R ; of the second 

 class those expected from R X DR crosses, and of the 



