284 



MYRA M. SAMPSON. 



PLATE I. 



Photomicrographs of Hetero-agglutination of Spermatozoa of Katharina 

 tunicata in a solution of cytolyzed spermatozoa of Strongylocentrotus purpu- 

 ratus. 



The spermatozoa form three-dimensional pin-wheels. 



Magnification X 60. 

 Magnification X 260. 



