26 FRANK R. LILLIE. 



for Strongylocentrotus. But they merely prove either that 

 Strongylocentrotus sperm is not so delicate an indicator as Arhacia 

 sperm, or that the method employed by Loeb was inadequate to 

 detect small quantities of fertilizin. In Arhacia the eggs con- 

 tinue to charge the sea-water with sperm-agglutinating substance 

 after complete removal of the jelly, whether by shaking and 

 repeated washings, or by HCl; and the substance continues to 

 be formed as long as the eggs remain fertilizable and living, no 

 matter how often the eggs are washed. The eggs of Arhacia 

 secrete the suhstance as I previously maintained. It is not merely 

 the "dissolved chorion.^' 



It might possibly be objected to this conclusion that the con- 

 tinued appearance of the agglutinating substance in egg suspen- 

 sions in sea-water after removal of the chorion indicated merely 

 previous adsorption of the substance of the chorion. But the 

 indefinite continuance of its production is inconsistent with the 

 idea of a mere secondary removal of an adsorbed substance. 

 The idea is also inconsistent with the fact that Nereis eggs have 

 no jelly at the time laying, but produce a similar sperm agglu- 

 tinating substance. In this form the jelly also is secreted by the 

 egg after insemination. 



Finally if it can be shown that the jelly of immature eggs is 

 entirely devoid of the sperm agglutinating substance, my position 

 that this substance is a later secretion of the egg is rigorously 

 proved. As noted above I maintained the probability of this 

 view in my previous paper (Study VI). This summer my first 

 experiments were undertaken to investigate this point anew. 



Fortunately the season was late, and not a single Arhacia was 

 ripe when I began work (June 8). This applied to males as well 

 as females: so it was impossible at first to secure ripe sperm as 

 indicator. I therefore made extracts of immature ovaries to be 

 kept for subsequent testing from three females (i, 2, and 3, 

 June 8). June ii extracts of ovaries in sea-water were made 

 from females 4, 5, and 6: numbers 4 and 6 contained only ovo- 

 cytes; No. 5 had a large number of ripe ova in addition. On 

 June 16 extracts 1-6 were tested with Arhacia sperm suspension: 

 I, 2, 3, 4, and 6 were absolutely negative; no agglutination. No. 

 5 gave a strong agglutination reaction lasting about one minute. 



