NEUROHUMORS 



41 



that a caudal band in Fundulus did not disappear uni- 

 formly as a whole but was subject to a gradual reduction 

 which beginning on the two lateral edges of the band 

 spread slowly toward its axis, the last portion of the 

 band to be seen. The steps in the peripheral disappear- 

 ance of the bands in Fundulus was demonstrated photo- 

 graphically by Parker (1935c) who succeeded with the 

 help of Abramowitz in photographing from hour to hour 

 identically the same area in a fading caudal band on 

 this fish. At the outset all melanophores across the 

 whole dark band had their pigment about equally dis- 

 persed (Fig. 28). Some nine hours later those on the 



Fig. 28. Caudal band of a living killifish a quarter of an hour 

 after it has been formed by the cutting of a single fin-ray. This 

 ray is represented at the region of the photograph by its four 

 branches. The pigment in all denervated melanophores is fully 

 dispersed. Parker, Proc. Amer. Philos. Soc, 1935, 75, pi. 3, 

 fig- Pl- 



edge of the band showed greater pigment concentration 

 than those near its axis (Fig. 29). Finally after about 

 two and a quarter days those near the axis had as con- 



