INITIATION OF DEVELOPMENT IN NEREIS. 3 



experiments- were performed during the morning and afternoon 

 following the evening that the worms were captured. A few 

 experiments were performed during the evening of capture. 



The point to be emphasized is that washing in sea-water so 

 modifies the eggs that they do not respond readily, or at all, to 

 parthenogenetic treatment. 



The Experiments. 

 The experiments with heat may be divided into four groups as 

 follows : 



1. The initial experiments in which the eggs were cut from the 



animals while in the warm sea-water. 



2. The experiments with dry eggs. 



3. The experiments with eggs in warm "serum." 



4. The experiments with washed eggs. 



I. The Initial Experiments. 



In the initial experiments, worms were cut in 5, 10, 25, 50^ 

 and 100 c.c. of sea-water at 30°, 32°, 33°, 34°, 35°, 36° C, the 

 worms removed and the eggs exposed for from five to fifteen 

 minutes. 



The following experiments selected from a number give the 

 details : 



(a) July 22, 1:45 P.M. A female put in 100 c.c. of sea-water 

 at 31° C. swims actively without discharging eggs. At 1:50,. 

 the temperature is 35° C. Eggs are cut out, the worm removed. 

 Ten samples of eggs are removed to 5 c.c. of ordinary sea-water 

 as follows: 2.03, 2:10, 2:25, 2:35, 2:45, 2:55, 3:05, 3:15, 3:25,. 

 3:35 P.M. 



At times the temperature rose to 36° C. and once to 36.5° C. 

 Many eggs at the time of removal from the warm sea-water 

 exhibited membranes standing off at an unusual distance, others 

 were darker than normal, and a few had disintegrated. Later 

 experiments showed that these changes are due to exposure at 

 too high temperature. Even five minutes exposure at 37° C. 

 will bring them about. The jelly is formed in the warm water, 

 and often at 35° C. or above it is dissolved and disappears. This 

 may be shown by examining eggs in India ink ground up in 



