18 E. E. JUST. 



were in turn tested. The supernatant sea-water from none 

 during ten hours gave an agglutination reaction. Ovarian 

 tissue, likewise, procured after removing the eggs by straining, 

 does not produce a sperm agglutinin. The fully matured egg 

 alone with or without jelly elaborates fertilizin. 



(c) Study of Perivisceral Fluid. Finally, repeated trials with 

 with perivisceral fluid from mature or immature females never 

 gave agglutination. Thus, at 2:40 P.M., July 3, drops of i per 

 cent. Echinarachnius sperm suspension placed on slides when 

 tested with perivisceral fluid from three females showed no 

 agglutination. Each of the three samples of fluid was then 

 diluted with clean sea-water 1/2, 1/4, 1/8, 1/16. The reaction 

 with fresh sperm suspension in all cases was negative. 



To sum up, we may say that mature Echinarachnius eggs in 

 sea-water give off a substance that agglutinates Echinarachnius 

 sperm; this substance the eggs will form in the absence of their 

 jelly hulls. Immature eggs do not secrete the agglutinin nor 

 does the ovarian tissue or perivisceral fluid. 



The agglutinin of Echinarachnius is more powerful than that 

 of Arbacia, as can be readily gleaned from a study of Lillie's work. 

 An equal quantity of Echinarachnius eggs will give off more 

 fertilizin in a given length of time than Arbacia eggs, but Echi- 

 narachnius eggs will cease production before Arbacia eggs. 

 This is doubtless correlated with the greater irritability of 

 Echinarachnius egg as evidenced both by its susceptibility to 

 mechanical agitation and its earlier loss of fertilizing power. 



It can be readily shown that this loss of fertilizing power is 

 gradual and farther that it runs parallel with lessening fertilizin 

 production. 



B. Fertilizin Production as an Index of Fertilization Capacity. 

 While it is true that only mature eggs are capable of producing 

 the agglutinin, this capacity varies between wide limits. One 

 cannot foretell, therefore, the agglutinin production of a given 

 lot of eggs in a given quantity of sea-water. Often eggs which 

 on microscopic examination are found to be fully matured yield 

 no agglutinating substance. Since, as shown above, immature 

 eggs do not secrete fertilizin nor does the jelly form it, the secre- 



