264 JOHN W. SCOTT. 



and if any chemical reaction was here involved it could not be 

 detected with the eye. The separation of these bodies appeared 

 to be a purely physical process. 



Since "the cilia are continuously active, independent of any 

 egg-laying period, it would seem that the egg-laying reaction 

 is a direct response to changes in the egg that are chiefly pro- 

 duced by the breaking down of the germinal vesicle. As noted 

 in an earlier paper a worm shows unusual muscular activity at 

 the time of oviposition. This muscular reaction may be due to 

 chemical changes in the body fluid, the irritation being produced 

 by materials escaping from the nucleus. However another ex- 

 planation is possible. As the ripened eggs begin to accumulate 

 in the nephridial sacs, excretion, the normal function of these 

 organs, would be hindered or stopped. This would lead to an 

 accumulation of waste in the part of the coelome posterior to 

 the diaphragm, and in all probability would act as an irritant 

 producing more vigorous muscular action until the eggs were 

 expelled. In this way the wave-like movements of the worm at 

 oviposition are a physiological response to an interference with 

 excretion. Though these suggestions are largely theoretical, 

 I am inclined to believe the latter view is the correct explanation. 



SUMMARY AND CONCLUSIONS. 



Amphitrite under normal conditions keeps up, with occasional 

 brief resting periods, a series of wave-like contractions of the body 

 for the purpose of sending water through its tube. A short time 

 before oviposition the wave-like movements become stronger and 

 slightly faster than usual. This excitement indicates the pres- 

 ence of ripe eggs and marks the beginning of the separating 

 process. After some time has elapsed, and the nephridial sacs 

 are well rilled, each contraction wave as it approaches the an- 

 terior end of the body forces out through the pores small slimy 

 streams of eggs. Oviposition usually continues from thirty to 

 sixty minutes. The process of separation has been previously 

 described. While the cilia furnish the motor power in separating 

 the ripe eggs, strong wave-like contractions of the body wall 

 furnish the pressure needed to expel the eggs from the nephridial 

 pouches. It is suggested that this unusual activity of the worm 



