20 



COLOR CHANGES IN ANIMALS 



fully blanched in about an 

 extreme degrees of tint in 



hour and ten minutes. The 

 these young fishes (Fig. 13) 

 were quite equal to those 

 of the adults, and the 

 pigment in their melano- 

 phores showed as much 

 concentration (Fig. 14) 

 and dispersion (Fig. 15) 

 as did that in the mature 

 fishes. When transverse 

 cuts were made in the fins 

 of these young fishes pale 

 bands developed (Fig. 16) 

 as in the adults. In all 

 these respects the newly 

 born pups of Mustelus 

 agree with the adults, 

 and they may be said to come into the world with 

 their chief systems of organs including their melano- 

 phores fully functional (Parker, 1936^). 



Fig. 16. Dorsal view of a 

 pectoral fin from a newly born 

 dogfish, Mustelus, showing two 

 pale bands as the result of small 

 transverse cuts. Parker, Biol. 

 Bull., 1936, 70, pi. 1, fig. i. 



