PARS INTERMEDIA AND PARS TUBERALIS 



tracts of the pars neuralis, which have been frequently em- 

 ployed, cause dispersion of the melanosomes or effects on 



Fig. 52. — The effect of an injection of an extract of the pars intermedia (ox) on 

 the dispersion of the melanosomes in the skin of the frog (Rana nigromaciilata). 

 Frog A received no injection; frog B received the extract. Top: before injection. 

 Bottom: after the injection of the extract into frog E. Particularly note the blacken- 

 ing of the skin of the back and flanks (indicated by the arrows, frog 5, top). 



other chromatophores because of the presence of some sub- 

 stance other than the oxytocic or the vasopressor hormone. 

 2. Urodela. — With the exception of the newt, Diemyctylus, 

 in which posterior-lobe extract was found to cause a concen- 



