320 ALFRED C. REDFIELD 



2. The daily rhythm of color change is caused by the direct 

 action of photic and thermal stimuli upon the melanophores or 

 some closely associated tissue (pp. 280 to 282, 284 to 289). 



3. The adaptive reactions of the melanophores depend upon 

 stimuli received through the eyes (pp. 290 and 291). 



4. The contraction of the melanophore pigment during nervous 

 excitement may be initiated by any noxious stimulus (pp.279 and 

 283). It is brought about by the cooperation of nervous impulses 

 delivered to the pigment cells by the sympathetic nervous system 

 (pp. 306 to 311) and the secretion of adrenin by the adrenal glands 

 (pp. 292 to 306). 



5. The resemblance between the innervation of melanophores 

 and smooth muscle is indicated (pp. 317 to 319). 



More detailed summaries will be found in the text at the end 

 of each section. 



