2/4 



MYRA M. SAMPSON. 



both Arbacia and of K. tunicata move anti-clockwise when in con- 

 tact with other objects may account for the shape of the pin- 

 wheels. 



Of the ten species tested in which the spermatozoa are inactive 

 in sea-water, iso-agglutination occurred in but one species, Kath- 

 arina tunicata. 



III. HETERO-AGGLUTINATION. 



i. GENERAL. 



Two distinct types of hetero-agglutination were obtained in this 

 investigation, one with sea-urchins and one with K. tunicata. 

 Hence their characteristics will be considered separately and com- 

 pared with other accounts of the phenomenon. 



Hetero-agglutination has been reported by Lillie (1913) between 

 Arbacia egg-water or blood and Nereis spermatozoa; by Glaser 

 (1914) between Arbacia egg-water and Astcrias spermatozoa, and 

 the reciprocal relationship between Astcrias egg-water and Arbacia 

 spermatozoa; by Just (1919) between Arbacia egg-water and 

 Echinarachnius spermatozoa; and by Loeb (1914) between 5". pur- 

 pu-ratus egg-water and 6*. franciscanus spermatozoa. Reciprocal 

 hetero-agglutination has been reported but once, as indicated above. 



Evidence is given here of hetero-agglutination of spermatozoa 

 of K. tunicata by solutions of cytolyzed spermatozoa of S. pur- 

 pur at us ; also by the blood of either S. purpuratus or 5". francis- 

 canus. The reciprocal relationship is also reported : hetero-ag- 

 glutination of spermatozoa of S. purpuratus and of S. franciscanus 

 by the blood of K. tunicata*. 



2. MATERIAL AND METHODS. 



The material and methods include those employed in iso-aggluti- 

 nation experiments. In addition, blood was collected and filtered 

 and solutions of cytolyzed spermatozoa of S. purpuratus and S. 

 franciscanus were prepared in the following manner : 



A 5 per cent, suspension of spermatozoa in glass distilled 

 water was allowed to stand at room temperature (15 C.) for one 

 hour, shaken at frequent intervals, and filtered (through Whatman 

 filter paper, No. 2 and No. 50) three times. 1 In order to make 



i Solutions made from spermatozoa which were allowed to cytolyze in dis- 



