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THE AMERICAN NATURALIST [Vol. XLV 



various stages. The study involves two incidental prob- 

 lems: (1) Source of the epidermal pigment, (2) cause of 

 degree of coloration of skin. These matters must re- 

 ceive consideration first. Then follows a discussion of 

 the bearings of the determined facts on the question of 

 color inheritance in crosses between whites and blacks, 

 or mulattos. 



Material— The material studied comprises 18 pieces 

 of skin taken from near the mid-line of the abdomen, 

 including 5 pieces from full-blooded negros of varying 

 grades of color, 6 pieces from mulattos of various 

 shades, 4 pieces from brunets, 2 from blonds, and 1 piece 



of pathologically pigmented skin; also a melanotic sar- 

 coma, several pieces of pigmented skin of incomplete 

 history, sections of infant's scalp and eyelid of new- 

 born mulatto. Individuals were classified as blond or 

 brunet according to color of hair. Mulattos were so ad- 

 judged in most cases from general appearance, i. e., 

 absence of distinct negro features, e. g., thick lips, flat 

 nose, etc., though in several cases the individual con- 



