Fig. 53. — Photomicrographs of the cutaneous melanophores of the frogs of Figure 52. 

 X99. I. Skinof back of frog 5, top (before injection). 2. Similar area of skin of back of frog 5, 

 bottom (after injection). 3. Skin of flank of frog y/, bottom (no injection). 4. Skin of flank of 

 frog B, bottom (after injection). 



