Bulletin of the Museum of Comparative Zoology 

 AT HARVARD COLLEGE. 



Vol. LIII. No. 1. 



THE LIGHT RECIPIENT ORGAN OF THE COPEPOD, . EUCALANUS 



ELONGATUS. 



By Calvin Olin Esterly. 



With Six Plates. 



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



PRINTED FOR THE MUSEUM. 



October, 1908. 



I 



