150 FRANK R. LILLIE AND E. E. JUST. 



he ceased. At 2:20 he was tested again with positive results for 

 the fourth time, and a Httle later was tested once more with 

 water charged by another female and shed sperm once more.' 



Thus each time that this animal was placed in sea-water that 

 had contained a female for a certain length of time he responded 

 instantaneously, and each time that he was removed and put in 

 fresh sea-water he ceased to shed sperm. 



This reaction is almost mechanical in its regularity, and can 

 be secured with almost any male in good condition. Cases 

 were found in which certain females apparently did not give off 

 the effective substance, but they were very rare. As a general 

 thing a large fully ripe female will so charge 125 c.c. of sea-water 

 in an hour's time that any active mature male will give the sperm- 

 shedding reflex almost instantaneously on being dropped in after 

 the removal of the female, whereas even repeated transfers from 

 one bowl of fresh sea-water to another causes no such response. 

 If a male and female be placed together in a bowl of fresh sea- 

 water they appear to stimulate one another very quickly, but 

 it is usually several minutes, at least in the case of animals that 

 have been kept in the laboratory over night, before the male 

 begins to shed sperm; and the female never sheds her eggs until 

 after the male has begun to shed sperm. 



We have seen that some kind of emanation from the female 

 incites the male to shed sperm. In the case of the female, 

 however, it is not any comparable emanation from the male, but 

 the presence of sperm in the sea-water that incites the shedding 

 of eggs. The females are much more apt to shed their eggs 

 spontaneously than the males to shed sperm. Apparently, when 

 fully mature, many females are unable to hold the eggs back. 

 But, in the case of those that do, it is impossible to cause the 

 egg-shedding reflex by putting them in water that has contained 

 males; on the other hand, the addition of a certain quantity of 



1 Mechanical shock, killing fluids, alcohol and fresh water, may cause the worms 

 to shed their sexual products; probably any sufficiently strong shock may act 

 similarly. But by slow addition of alcohol to the sea-water the animals may be 

 .stupefied and die extended without shedding the sexual products. Worms freshly 

 caught react more surely to secretions of the female than those that have been in 

 the laboratory over i8 hours. The reactions are not so definite in the late after- 

 noon of the day after capture, and this is associated with a general lowering of tone. 



