54 HEREDITY AND EUGENICS 



nished the straight t3^pe of hair. Hair was classed 

 as straight when the relative diameters in cross- 

 section were 100:90 or over, wav}^ when 100:70-90, 

 and curly when 100:60-70. In 31 families in which 

 the cross was wavy X straight or curh' x straight, 

 there were i 57 children, of whom 84 had straight hair 

 to 73 curly or wavy. This approximates to a Men- 

 delian i : i ratio; but dominance, when it occurs, is 

 variable, and although segregation occurs to some ex- 

 tent, there is no close conformit}' to simple Mendelian 

 behaviour. Wav}^ is regarded as a heteroz^'gote of 

 curly and straight, curh^ being recessive, but there 

 is no sharp line between wavy and curl}'. W^avy x 

 wavy gives all three types in approximately^ equal 

 proportions. Straight X straight gives all three 

 types, but with a large preponderance of straight. 

 Curh' X straight gives mostly straight if the father's 

 hair is straight, but more curly if the father's hair 

 is curly. These results for Filipinos appear to be 

 general!}' the reverse of those obtained in America. 

 (See photographs in Journal of Heredity 7:412 [191 6].) 

 Bond (191 2) cites certain cases of negro-white crosses 

 in which wavy and kinky hair both appear in the 

 same individual, the hair being wavy on the vertex 

 and kinky on the sides of the head. Three such 

 cases are figured. 



In a little-known work on the hair of mankind, 

 Friedenthal (1908) gives descriptions with numerous 

 coloured plates showing the distribution of hair on 

 the human body, and the extremes of plus and minus 

 variation in various races of man and in some apes. 

 Aino of Japan are figured, in some of which almost 

 the entire body has a hairy covering, and these are 

 compared with certain European variations in which 

 the whole face is covered with hair. Darwin* cites a 

 Siamese family which for three generations had the face 



* Animals and Plants, i. 448. 



