\^^'\ 



Bulletin of the Museum of Comparative Zoology 



AT HARVARD COLLEGE. 



Vol. LIIT. No. 6. 



THE EFFECT OF COLORED LIGHT ON PIGMENT-MIGRATION 

 IN THE EYE OF THE CRAYFISH. 



By Edward C. Day. 



With Five Plates. 



CAMBRIDGE, MASS., U. S. A.: 



PRINTED FOR THE MUSEUM. 



December, 1911. 



