286 



Part III. — Tweniy-fourth Annual Report 



The quantity of eggs obtained from No. 2 on 19th March was small, 

 and there was a pause until the 26th, when the spawning began in reality. 

 In the case of this fish the emission of eggs went on very steadily until the 

 19th April, eggs being got daily. From 19th to 22nd April spawning was 

 interrupted, and the last eggs were obtained on 23rd April. The spawn- 

 ing of this female thus extended over a period of 36 days from first to 

 last, but was chiefly limited to the interval from 26th March to 23rd April, 

 or 28 days; only on three days in that time were no eggs found to have 

 been spawned. 



The characters of the spawning of this fish were a regular, small or 

 moderate, quantity of eggs on each day. The average number emitted per 

 day for the 25 days that they were emitted was 6542 ; the largest on any 

 one day was 15,195 on 17th April, the next largest being 13,832 on 17th 

 April; the smallest was 2056 on 19th April, and 2525 on 29th March. 



The other female, in tank 5, offered a striking contrast to the above. 

 Its spawning extended over a period of 41 days, viz., from 26th March to 

 5th May; but eggs were spawned on only 16 days during that time. 

 There were thus long intervals without any eggs being obtained ; as much 

 as nine days. As the Table shows, it spawned most regularly at first, 

 each day from 26th March to 2nd April (no collection was taken on the 

 28th or 1st). It will be noticed that the quantity of spawn emitted on 

 the second day was very large, and it then diminished, only 155 eggs being 

 found on the 31st March, and only 88 on 2nd April. The ovaries were 

 greatly distended when spawning began, and the figures show that the 

 fully mature eggs which had collected were got rid of in about five days, 

 after which a rest for some days occurred. 



This female spawned again on the 7th April, and for the next two days ; 

 then not again until the 15th; then on the 19th, 22nd, and 23rd; then 

 on the 26th, and finally on 5th May. The seven "bursts" of spawning 

 were as follows : — 



Dates. 



Number of 

 Eggs Spawned. 



Ratio per 

 1 C.C. 



26th March-2nd Apr 

 7th-9th April, . 

 15th April, 

 19th April, 

 22nd, 23d April, 

 26th April, 

 5th May, . 



65,657 

 47,797 

 49,170 

 32,828 

 30,831 

 15,587 

 10,907 



255-64 



272-2 



364-9 



314-6 



331-4 



306 '0 



318-0 



The largest numbers on any one day was 49,170 on 15th April, and 

 44,405 on 27th March ; the smallest daily amount was 88 and 155, which 

 might almost be considered accidental, the next being 2555. The average 

 per day for the 15 days on which spawning occurred was 16,852 eggs. 



The aggregate quantiiy of spawn from No. 2 over the whole period was 

 654*29 cubic centimetres, and the estimated number of eggs was 163,557. 



The aggregate from No. 5 was 856-79 cubic centimetres, and the 

 estimated number of eggs was 252,777. 



[Table. 



