14 CAREY P. McCOED 



and was so markedly absent in the control groups, that the phenomenon 

 was made the subject of special study. 





Figs. 2 and 3. Drawings of the same tadpole (Rana pipiens) just prior to 

 (Fig. 2), and forty-five minutes after (Fig. 3), pineal feeding, showing the transient 

 loss of pigment due to action of pineal constituents on the melanophores. Inserts in 

 lower right hand corners show appearance of melanophores in each condition. (After 

 McCord and Allen, J. Exper. Zool.) 



Eggs of the species Rana pipiens, Rana cantabrigiensis and Bufo amer- 

 icana were collected in the vicinity of Detroit, and hatched in the labora- 



