40 EGG AND SPERM SUBSTANCES 



elusions concerning the cellular origin of the echinoid egg jelly 

 must await further study. Perhaps an investigation of the cellular 

 origin of the echinochrome bodies in sanddollar egg jellies might 

 be rewarding in this regard. 



Although the jelly surrounding the sea urchin egg is clearly 

 the main source of fertilizin, studies indicate that fertilizin or fer- 

 tilizin like material may also be obtained from less superficial 

 regions of the egg. Thus Motomura ( 1950a ) reported extraction 

 of a sperm agglutinin from unfertilized, jellyless S. piilcherrimus 

 eggs by prolonged standing in sea water, by boiling, and by shak- 

 ing jellyless, fertilized eggs to break the fertilization membranes. 

 On the basis of these experiments Motomura concluded that the 

 sea urchin egg produces a second sperm agglutinin, cytofertilizin. 

 Following certain objections to these experiments (Byers, 1951) 

 Motomura (1953a,b) extended his studies. He found that the 

 surrounding sea water becomes charged with sperm agglutinin 

 upon hatching of blastulae from jellyless eggs. Furthermore, 

 jellyless eggs treated with NaSCN to remove the vitelline mem- 

 brane charge the sea water with agglutinin during the first ten 

 minutes after fertilization. Finally Temnopleurus hardeivickii 

 eggs normally fail to produce a satisfactory agglutinating egg 

 water, but after removal of the jelly and membranes fertilized 

 eggs, blastulae or gastrulae of this species charge the sea water 

 with sperm agglutinin. The exact source of Motomura's cytofer- 

 tilizin has yet to be established, but the hyaline layer material of 

 the egg is one likely possibility ( Tyler, Monroy, and Metz, 1956 ) . 

 This view is supported by cytochemical studies at least to the 

 extent that the egg jelly, the hyaline layer material and the cor- 

 tical granules give positive tests for acid polysaccharides ( Monne 

 and Slautterback, 1950; Monne and Harde, 1951). 



According to Motomura's experiments the egg jelly fertilizin 

 and cytofertilizin have different pH optima for extraction. This 

 suggests that they may be chemically different, although it may 

 only reflect differences in bonding of the same agent. In any 

 event a comparison of the biological properties of the two agents 

 should be made. Information on the specificity of cytofertilizin 

 agglutination and the effect of cytofertilizin on sperm that have 



