Vol. X] VON GELDERN—SKIN OF ANGUS CAROLINENSIS ' 99 



at the periphery of the scale where they more closely approach 

 the surface. A few cell bodies lie above or below this imaginary 

 line, but in thick sections the bodies of the melanophores form a 

 fairly thick, dark-brown layer of fairly regular width. 



The melanophores are best studied in vertical sections of the 

 fixed material stained with haematoxylin and eosin. It was found 

 unnecessary to use the methods adopted by Keller and others to 

 bring out the finer branches of these cells, for in most of the prepa- 

 rations these were clearly visible. 



The cell body is more or less rounded but considerable difference 

 exists among them, some being much narrower than others (Figs. 

 II and 12). The surface facing the epidermis is often concave but 

 rarely it may be convex or apical. The nucleus may be round, 

 oval, reniform, horseshoe-shaped or even double in rare instances. 

 In some preparations it takes a fairly deep blue stain and has a 

 vesicular appearance (Figs, ii, 15 and 17). The concavity when 

 present is directed towards the epidermis. 



Coming off from the sides of the outer surface of the cell body 

 are a varying number of permanent branches which run either 

 vertically toward the inner surface of the epidermis or present a 

 lateral curvature. The curvature may even be so marked that, 

 at the proximal part, the branches may be directed first down- 

 wards and laterally and then gradually curve laterally and up- 

 wards (Figs. II, 12, 13 and 15). These^ranches run through the 

 spaces among the leucophores and, as they approach the surface, 

 lateral branches in turn give off further branches. This tree-like 

 branching continues until beneath the under surface of the epi- 

 dermis a layer of fine terminal branches exists. 



The contents of the melanophores consists of a varying amount 

 of fine pigment granules imbedded in a mass of faintly brown, 

 poorly staining cytoplasm. The arrangement and distribution of 

 the pigment granules depends on the color state of the skin, being 

 almost absent in the smaller branches in the green state but present 

 even in the terminal branches in the brown state. Under the oil 

 immersion lens the poorly staining cytoplasm may be followed 

 even in the finest branches lying beneath the epidermis. Follow- 

 ing them is, however, greatly facilitated by the presence of isolated 

 pigment granules which have failed to migrate with the general 

 mass of pigment. . 



The pigment granules are oval in shape and brown under 

 magnification. Their number varies markedly, irrespective of the 



