302 



A. IZUKA. 



Text-figure 3. 



The embroy of o, days 

 old, with 4 setigerous 

 segment*. 140/ 1. Nat. 



She. 



lasting a few days ; that the period begins on the night just before the day 

 of the new or the full moon in the middle or the latter part of the month 

 mentioned ; that it invariably takes place in the mid night just after the 

 flood-tide ; and further that very rarely it occurs in two periods, close to 

 the consecutive new and full moons. 



After making observations for myself, I am convinced of the general 

 accuracy of the fishermen's predictions as to the time when the swarming 

 should take place. 



The first swarming of the year 1906 occurred on the night of Dec- 

 ember 1 5th. On that day the worms that swarmed out were observed to 

 be very few, but on the following day (the day of the new moon) the 

 swarm proved to be one of the largest of that year. 



For an illustration I may describe the swarming of that day, i.e. the 

 1 6th December, 1906. Before proceeding further, it would be well to 

 give some notes about the place in which the swarming occurs. As 

 Kojima Gulf (text-figure 4) stands in connection with the open Inland Sea, 

 by a narrow channel, the hours of the flood and ebb tide differ very much 



