524 



of sodium aud potassium salts which contained enough potassium to 

 contract the melanophores and in which the irritability is preserved 

 for some hours. The same cell was then photographed in the con- 

 tracted condition. Finally, the scale was returned to the original so- 

 dium chloride solution and, after the expansion was completed, it 

 showed that the processes were identical with those of the first pho- 

 tograph. This experiment was repeated many times and in every 

 case the result was the same. (See Figs. 1 — 3.) 



Thus in F. heteroclitus the processes of the melanophores remain 

 constant and the apparent changes of contour are due to migrations 

 of the melanin granules within the fixed processes. This result is 

 in full agreement with the conditions observed by Keeble and Gamble 

 in Macromysis, by Degner in Praunus, and by Kahn und Lieben in 

 Rana, 



Bibliography 

 Ballowitz, E., : 93. Über die Bewegungsersclieiiiungen der Pigmentzellen, 



Biol. Zentralbl., Bd. 13, p. 625—630. 

 Biedermann, W., : 92. Über den Farbenwechsel der Frösche. Arch. f. d. ges. 



Physiol., Bd. 51, p. 455-508. 

 Degner, D., :12. über Bau und Funktion der Krusterchromatophoren. Eine 



histologisch-biologische Untersuchung. Zeitschr. f. wiss. Zool. Bd. 102, 



p. 1—78, 8 Textfig., 3 Taf. 

 FiCALBi, E., :96. Ricerche sulla struttura minuta della pelle anfibi (Pelle degli 



anuri della famiglia delle Hylidae). Atti R. Acad. Peloritana in Messina,^ 



Anno 11 (1896—97), Messina. 

 GoLoviNE, E., :07. Etudes sur les cellules pigmentaires des vertebres. Anna- 

 les de 1 'Institut Pasteur, Annee 21, p. 858—881. 

 Hooker, D., :12. The Reactions of the Melanophores of Rana fusca in the 



Absence of Nervous Control. Zeitschr. f. allgem. Physiol., Bd. 14, p. 



93—104, 3 Fig. 

 Kahn, R. H., und Lieben, S., :07. Über die scheinbaren Gestaltsänderungen 



der Pigmentzellen. Arch. f. Anat. u. Physiol., Physiol. Abt., p. 104—112. 

 Keeble, F., and Gamble, F. W., :04. The Color-Physiology of Higher Cru- 

 stacea. Philos. Trans. R. Soc. London, Vol. 196, p. 295—388, 6 PI. 

 Lieben, S., :06. Über die Wirkung von Extrakten chromaffinen Gewebes 



(Adrenalin) auf die Pigmentzellen. Zentralbl. f. Physiol., Bd. 20, p. 



108—117. 

 Winkler, F., :10. Beobachtungen über die Bewegungen der Pigmentzellen, 



Arch. f. Derm. u. Syph., Bd. 101, p. 255—260. 



