Bulletin of the Museum of Comparative Zodlogy 
AT HARVARD COLLEGE. 
Vow RITE Now tk. 
THE LIGHT RECIPIENT ORGAN OF THE COPEPOD, EUCALANUS 
ELONGATUS. 
By Catvin Ouin ESTERLY. 
Wit Srx PuatEs. 
CAMBRIDGE, MASS., U. S. A.: 
PRINTED FOR THE MUSEUM. 
OcToBER, 1908. 
