UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 11, No. 7, pp. 143-154, pis. 5-6 September 24, 1913 



OBSEKVATIONS ON ISOLATED LIVING 



PIGMENT CELLS FROM THE LARVAE 



OF AMPHIBIANS 



BY 

 S. J. HOLMES 



It has long been a mooted question wliether the movement 

 of pigment in chromatophores is due to the change in outline of 

 the cell itself, or to the flow of pigment within cell processes 

 which remain comparatively constant in form. Briicke (1852) 

 in his classical memoir on the color changes of the chameleon 

 was among the first to champion the latter view, and since his 

 time the majority of workers who have carefully studied the 

 movements of chromatophores in vertebrates have come to the 

 same opinion. Virchow, Harless, von Wittich, Lister, Ehrmann, 

 and Gaupp have ascribed the color changes in amphibians to 

 movements of pigment within the cell. Biedermann (1892) in 

 his thorough paper on the color changes of Hyla describes pro- 

 cesses of the chromatophores devoid of pigment, but he leaves 

 the question open as to the method of pigment distribution. 

 While pigment may be withdrawn from and extend into the 

 cell processes, the latter may nevertheless, according to Bieder- 

 mann, be capable of amoeboid movement. H. Miiller (1860) 

 likewise takes an undecided position on account of the difficulty 

 of deciding between the alternative views. 



The versatile histologist Leydig (1876), on the other hand, 

 regarded the amphibian melanophores as amoeboid cells, a view 

 more recently defended by Ficalbi (1896) and by Galovine 

 (1907). 



