Mechanism of Pigment Migration within Teleost Melanophores 



215 



Fig. 3. Fibrillar zone of a contracted melanophore, the width being about 3.5 microns. Magnification 20,000. 

 Fig. 4. Fibrillar zone of a dispersed melanophore, the width being about 0.4 micron. Magnification 17,000. 

 Fig. 5. Longitudinally cut fibrils. Magnification x 33,000. 

 Fig. 6. Transversely cut fibrils. Magnification < 55,000. 



membranes. The width of this fibrillar zone varies 

 with the pigment dispersion. By fully dispersed 

 melanophores the width is about 0.5 n and by fully 

 concentrated melanophores the width is about 3 n 

 (figs. 3-6). 



The fibrils are regarded as representing contrac- 

 tile structures, which as a basket mesh-work surround 

 the inner sack. Thus when the fibrils contract, the 



Fig. 7. Schematic representation of the observations made on 

 teleost melanophores. 



sack diminishes and the pigment granules are con- 

 centrated. On the other hand when the fibrils relax, 

 the sack can increase and the granules will be dis- 

 persed. The suggestion is thus made that the migration 

 of the pigment granules within the teleost melano- 

 phores should be due to the contracting and relaxing 

 fibrils in the zone between the two cell membranes. 

 From a physiological point of view it also seems to 

 be the concentration of the pigment granules that 

 requires most energy. 



This investigation gives a completely new explana- 

 tion of the mechanism of pigment migration within 

 teleost melanophores. It abolishes many previous 

 theories of pigment migration (1. 3-9). 



This work has been supported by a grant from the 

 Kungliga Fysiografiska Sallskapet, Lund. 



References 



1. Ballowitz, E., Pfl tigers Arch. ges. Physiol. 157, 165 (1914). 



2. Du Buy, H. G., Woods, M. V.. Bdrk, D., and Lackey, 



M. D., /. Nat. Cancer Inst. 9. 325 (1949). 



3. Franz, \.,Z.Zellforsch. 30, 194(1939). 



4. Hooker, D., Amer. J. Anai. 16, 237 (1914). 



5. KoLTZOFF, N. K., Compi. rend. acad. sci. URSS, N.S. 28, 



554 (1940). 



6. Marsland, D. a., Biol. Bull. Hoods Hole 87, 252 (1944). 



7. Schmidt, W. J., Biol. Zentr. 39, 140 (1919). 



8. Shanes, A. M. and Nigreli i, R. F.. Zoologia 26, 237 



(1941). 



9. Wright, P. A. and Sabal, J., Biol. Bull. 103, 312 (1952). 



