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DAVENPORT HOOKER 



in the center of the cell so thickly that its granular nature is 

 visible only at the periphery; to one side of the pigment lies the 

 cell nucleus, usually rounded, though in some cases it appears 

 almost hour-glass shaped; surrounding pigment and nucleus is 

 a thin layer of cytoplasm, faintly granular in appearance which 

 has a definite external border and which presents no sign of 

 processes. Around the outer edge of the cytoplasm and usually 

 separated from it by a clear space is a circle which enlarges or 



¥[^. 1 An expanded mehuiophoic from a tadjiole of Rana pipiens in its space 

 in the connective tissue. Cross-section. 



Fig. 2 A contracted melanophore in the subeindermal connective tissue sheet, 

 seen from above. The figure shows the pigment, nucleus and cytoiihism of the 

 cell and the cavity within which it lies. 



diminishes in circumference on changing the focus and which 

 represents a section of the convex upper wall of the cavity. 

 Every cell which is fully contracted or nearly so demonstrates 

 this cavity wall. The space contained inside of this line is in 

 no way commensurate in size with the area taken up l)y the 

 expanded cell. ^ 



The reason for this is made clear by cross sections of a con- 

 nective tissue sheet containing contracted melanophores. Such 



