Abstract
Homologous antisera against purified fertilizin, and against extract of fertilized eggs of Lytechinus pictus have been shown to temporarily increase the respiratory rate of the unfertilized eggs of Lytechinus variegatus. Parallel experiments employing antisera against fertilizin of Strongylocentrotus purpuratus and unfertilized S. purpuratus eggs yielded essentially negative results. Further experimentation is necessary before this apparent difference between the responses of the eggs of these 2 species to antisera against fertilizin can be resolved. Antisera against fertilizin of S. purpuratus were effective in increasing the respiratory rate of unfertilized L. variegatus eggs, indicating the presence of antibody capable of effecting increased respiration. Normal sera and antiserum against sperm were without measurable effect on the respiratory rate of L. variegatus eggs. None of the eggs treated with antisera against fertilizin showed morphological evidence of activation.