4 repokt on the spawning of the common sole. 



11. Datks and Times of Spawning of the Sole. 



I obtained uufertilized eggs of the sole on April 3rd and 7th, but on 

 April 12th 1 found fertilized eggs for the first time. Then, again, on April 

 20th and 2 1st there were only unfertilized eggs. From this time onward, 

 however, fertilized eggs were found during the rest of my stay at the 

 Laboratory, sometimes on two consecutive days, sometimes with one 

 day's, sometimes with two days' interval ; and unfertilized eggs were the 

 exception. Thus fertilized sole eggs were obtained on April 23rd, 25th, 

 2(3th, 28th, May 1st, 2nd, 4th, 7th, 8th, 10th. Then on May 11th, 12th, 

 and 13th there were only a few eggs each day, of which the majority 

 were unfertilized, and then again a plentiful batch of fertilized eggs on 

 May 16th. 



The time of day at which spawning occurred seemed to get earlier as 

 the weather got warmer. Thus, during the last week of April, the eggs 

 would be in the first segmentation (two blastomere) stage between 6 and 

 7 p.m., which, according to subsequent observations, would point to 

 their having been spawned about, or rather before, 4 p.m. ; but later on 

 the egg-laying would begin about noon. On one occasion, when it began 

 about 11.30 a.m., it was not ended before 2 p.m., which is not so 

 surprising, since, as will be explained later, the eggs seem to be shed 

 one at a time. - 



111. On the AppeaPvANge of the Ovapies duping the Spawning 



Season. 



On May 15th, as it seemed desirable that the state of the ovaries 

 under these known conditions should be studied, it was decided to 

 sacrifice one of the females, of which there were a fair number 

 spawning, and preserve the ovaries for histological study. 



I first tried whether any ripe eggs were to be obtained from the living 

 fish, but without success ; and on opening the dead fish there seemed to 

 be no quite ripe eggs in the cavity of the ovary tube. This, it may be 

 remembered, was a day on which none of the other fish spawned, though 

 they did on the next day. Judging by the number of fish spawning in 

 the tank and the number of eggs spawned, the number of eggs ripening 

 each day must have been small proportionately to the eggs in the ovary, 

 which is not, of course, surprising, if the spawning is destined to be kept 

 up, on the average every other day, for a period of three months or so. 

 The ova were of all sizes. The largest and most transparent ones, 

 presumably those most nearly ripe, were distributed singly among those 

 less ripe over the whole laminar surface of the ovary, and did not seem 

 to be confined specially to one region of the ovary. However, the third 



