XEUROHUMORS 



53 



Fig. 38. Pale phase (above) and dark phase (below) of the 

 common catfish, Ameiurus. Parker, Jour. Exp. Zoo!., 1934, 69, 

 pi. 1, fig. 1. 



Fig. 39. A catfish, Ameiurus, into which an injection of olive- 

 oil extract of the dark fins and skins of five other catfishes had 

 been made anteriorly from the black dot below the adipose fin. 

 The resulting dark area is superficial to the region where the 

 injected fluid escaped from the needle point. Parker, Jour. Exp. 

 Biol., 1935, 12, pi. 1, fig. 2. 



