246 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



Black over yellow (dusky yellow). This shank color is simi- 

 lar to that described immediately above with the addition of 

 lipochrome pigment in the epidermal layers. 



Black over white (spotted). Here are found black spots in 

 an otherwise white shank. As in the black-over-green color 

 mentioned above, the epidermis in the spotted portion is thickly 

 peppered with black-brown pigment granules in both layers, and 

 f rec[uently supplied with melanin pigment cells in the rete layer. 

 The latter type of pigment is usually found in considerable 

 quantities in that part of the upper corium directly under the 

 spotted region, and to a less degree throughout the corium gen- 

 erally. Lipochrome pigment is lacking. 



Black over yellow (spotted). This shank color is due to the 

 same pigmentation as that described immediately above with 

 the addition of orange-yellow pigment in the epidermis. 



Black over blue. This type may be identical with the black- 

 over-green color described above with the exception that lipo- 

 chrome pigment is not present. 



Blue under ivhite. This is a white skin mottled with blue 

 blotches or spots. It is nothing more than a white skin and an 

 irregular distribution of melanin pigment cells in the upper 

 dermis. 



In all these conditions in which black masses overlie the other 

 colors, the pigment granules are often in much greater numbers 

 than in shanks in which a uniform black color is found. These 

 granules in the epidermis and cells (in the rete layer) are at 

 times so numerous that an intense black color is given the scale 

 without any assistance from the pigment cells in the cutis. Old 

 birds tend to possess these irregular markings more than do 

 young. 



Pink. — This color is a modification of white, due probably to 

 an abundance of capillaries in the dermis, and possibly also to 

 thin and unusually transparent scales. 



Red. — This color probably results from a congestion of blood 

 in the dermis. 



