280 



MYRA M. SAMPSON. 



K. tunicata; and (C) a questionable third type "clumping," de- 

 scribed by Glaser for Arbacia. (The "clumps" are irregularly 

 distributed and resemble aggregation rather than hetero-agglutina- 

 tion.) A summary of the results is given in Tables III. and IV. 

 These tables also include results first reported by Glaser, Just, 

 Lillie, and Loeb, as indicated by the initials in brackets. 



TABLE III. 



HETERO-AGGLUTINATION OF SPERMATOZOA OF CERTAIN MARINE ANIMALS 



(WOODS HOLE, MASS.). 



The letters A and C refer respectively to the strand formation (Lillie, 1913) 

 and clumping (Glaser, 1914) described in reports on hetero-agglutination. 



IV. SUMMARY. 



1. Iso-agglutination occurs in the black chiton, Katharina tuni- 

 cata. This is the first report of unmistakable iso-agglutination of 

 spermatozoa of a mollusc ; also of iso-agglutination of spermatozoa 

 which are inactive in sea-water. 



2. The iso-agglutinated masses of spermatozoa of K. tunicata 

 differ from those of sea-urchins and of Nereis. In the former 

 the agglutinating masses resemble three-dimensional pinwheels. 



