Xo. 536] 



COLOR INHERITANCE 



455 



are non-motile. He describes a network of pigmented 

 cutis cells (cliromatophores) connected with the epi- 

 dermis by processes through which the pigment granules 

 stream into the epithelial cells of the rete mucosum 

 Malpighi. He also concludes that the pigment arises 

 from the haemoglobin of the red cells, since the pigment 

 cells are most abundant in the vicinity of the blood ves- 

 sels. The reception of the pigment granules by the 

 epithelial cells he regards a phagocytic process, the epi- 

 thelial cells being described as corroding the processes 

 and assimilating the contents as part of their own organi- 

 zation. The important observations of Jager (1885) on 

 pigment spots in dog and rabbit after inflammation, and 

 those of R. Krause (1888) on apes, are in substantial 

 accord with those of the afore-mentioned investigators, 

 more particularly in regard to the secondary origin of 

 pigment in the epidermis, and the primary source of the 

 same in the blood. For further information regarding 

 literature of pigment cells, more particularly in the lower 

 vertebrates, the reader is referred to the splendid article 

 by Karg. 



It remains to outline more fully Karg's position as 

 representative of the second view above stated. Pig- 

 mentation of epidermis and its appendages (hair, etc.) 

 is a secondary process. The pigment is transferred to 

 the epithelial cells through cells which have their origin 

 in the cutis (*. e., chromatophore, Ehrmann). They 

 wander into, or, remaining on border line between epi- 

 dermis and cutis, send processes into the imVivlhilar 

 spaces of the epidermis. They end in the epithelial cells 

 (capable of a certain amount of amoeboid motility) to 

 which they surrender their pigment through process of 

 absorption causing streaming from process to cell. 

 These pigmented cells are wandering cells of the nature 

 of connective tissue cells. They are thought to obtain 

 their pigment from the blood. This, however, is not re- 

 garded as hemoglobin since no red corpuscles are ever 



