C. B. METZ 49 



Although sea urchin fertiHzins have been examined most thor- 

 oughly, some information on the chemistry of a few other ferti- 

 lizins and egg jellies is available. The invertebrates include 

 Megathtira and Nereis. Megathura fertilizin (Tyler and Fox, 

 1940), like sea urchin fertilizin, is nondialyzable, precipitates 

 with protein precipitants, and gives color tests for proteins. Sim- 

 ilarly the nitrogen content (4 to 5%) of both is low. Megathura 

 fertilizin is more stable to heat, acid, and proteolytic enzymes 

 than sea urchin fertilizins. Possibly this is related to the fact that 

 the Megathura sperm agglutination does not reverse spontane- 

 ously (Tyler, 1940a). Tests for univalent Megathura fertilizin 

 following inactivation have not been reported. Nereis egg jelly 

 has been examined by Ferry (cited by Costello, 1949) and Tyler 

 ( 1938b ) . According to the former, the material contains less than 

 1% nitrogen, at least 75% carbohydrate, part or all of which may 

 be uronic acid, and considerable bound inorganic material. Tyler 

 found that the jelly contained about 5% nitrogen and at least 

 18% reducing sugar. The fertilizins and egg jellies of some verte- 

 brates have been examined chemically. The forms include the 

 trout (Hartmann et ah, 1947) and amphibian (Minganti, 1955). 



Antifertilizin from Eggs 



Lillie (1914) observed that egg water from cytolyzed sea 

 urchin eggs failed to agglutinate sperm strongly. From this Lillie 

 concluded that an agent, antifertilizin, was released from within 

 the egg upon cytolysis and that the agent combined with and 

 neutralized the fertilizin. Later the agent was obtained in active 

 form by freeze-thawing jellyless eggs (Tyler, 1940b). Solutions 

 of the agent form precipitates with and inactivate the sperm ag- 

 glutinating action of fertilizin. They also precipitate egg jellies 

 and agglutinate eggs. 



The antifertilizin is not highly specific, for Tyler (1948a) ob- 

 tained cross reactions between related echinoids. Extracts of 

 Arhacia lixula and Paracentrotus lividus eggs give an unexpected 

 specificity pattern when tested in the presence of electrolytes 

 (Runnstrom and Monroy, 1950). Arhacia extract was relatively 

 specific whereas Paracentrotus extract was strongly active only 



