LITERATURE CITED. 47 



The following hypothesis is supported by the facts: That there 

 are two (double) factors {A and B) for black pigmentation in the full- 

 blooded negro of the west coast of Africa. 



There is no sex-linkage in skin pigmentation of man. 



Colored persons tend to select as consorts persons of about their 

 own grade of skin color. 



The yellow element in the skin color of light-colored persons and 

 those with Chinese blood is frequently high (about 25 per cent). This 

 excessive yellow element, obscured in full blacks, is revealed in diluted 

 black. 



The tradition that a person with negro blood who passes for white 

 may have, by a white consort, a child with a black skin color probably 

 depends on the observation that two "Hght-colored persons" may have 

 a medium-colored child. 



The darkest grades of eye color are rarely simplex or heterozygous ; 

 the simplex forms are chiefly hazel and light brown. 



The darkest grades of hair color are chiefly or exclusively duplex 

 in respect to dark pigmentation. 



Curliness of hair in the positive condition; when lacking in both 

 parents it is lacking in their children. Woolly hair is the duplex con- 

 dition. Wavy -haired persons always, and curly-haired persons some- 

 times, may carry "absence of curliness" in the germ-cells. 



It is not generally true that hybrids between whites and blacks 

 are relatively infertile; some such hybrids show an exceptionally high 

 fecundity. 



There is a strong correlation between skin and hair color, about 

 0.44 (where the greatest possible correlation is i.oo). 



There is no correlation between skin color and the curliness of 

 the hair. The determiners of both traits segregate in the germ-cells 

 of the hybrids and make unions at haphazard in the next generation. 



K.— LITERATURE CITED. 



Adachi, B. 



1903. Hautpigment beim Menschen und bei den Affen. Zeitschr. f. Alorphol. u. 



Anthrop., vi, 1-131. Taf. i-iii. 

 Bateson, W., and R. C. Punnett. 



191 1. The Inheritance of the Peculiar Pigmentation of the Silky Fowl. Jour, of 



Genetics, i, pp. 185-204. August. 



BlOCH, a., et P. ViGIER. 



1904. Recherches histologique sur le follicule pileux et le cheveu de deux n^gres 



decedcs a Paris. Bull, et Mdm. de la Soc. d'Anthropol. de Paris (5), v, pp. 

 124-132. 

 Bond, C. J. 



19 12. On Heterochromia Iridis in Man and Animals from the Genetic Point of View. 



Jour, of Genetics, 11, pp. 99-129, plates vi, viii. 

 Brodnax, B. H. 



1903. Color of infant negroes. Mississippi Med. Record, vii, p. 174. 

 Broca, P. 



1863. Coleur de la pcau du N^gre k la naissance. Bull. Soc. d'anthrop, Paris, iv, 



pp. 612, 613. 



1864. The Phenomena of Human Hybridity. Trans, by C. C. Blake. London, 76 pp. 



