of the Fishery Board for Scotland. 289 
I have elsewhere shown* that at the last stayes of the maturation of 
plaice eggs in the ovary the absorption of water by the eggs is enormous, 
amounting to at least two-thirds of the volume of the contents. Thus, in 
the 654 cubic centimetres of eggs produced by the female, No, 2, at least 
536 cubie centimetres is represented by water absorbed not long before 
the eggs are extruded, and which is secreted by the fish. So in the other 
case ; about 572 cubic centimetres of the 857 cubic centimetres of eggs 
represents water absorbed. 
Both the plaice were kept in the tanks after the conclusion of spawning. 
On 9th May, no further eggs having come from the plaice in No. 2 since 
the 23rd of April, and spawning being clearly over, she was killed and 
examined. The length was the same, 46°5cm., and the weight was 2lbs. 
8ioz. (1139-8 grammes), showing a loss of 140z., or 396 grammes. 
At the same time, the other plaice (No. 5) was also weighed. It was 
2lbs. 640z. (1083 grammes), showing a loss of 8 j0z., or 234 grammes. 
The measurement was a little less, viz., 46°7cm. 
This fish was put back with the males into the tank, but no further 
spawning occurred. On 13th May she weighed 1119 grammes, and was 
still 46-7em.; on 21st May the weight and length were the same, so that 
recovery was slow. 
The loss in weight above referred to does not represent anything like 
the weight of the eggs spawned. Among those of No. 2 it was found 
that 56 cubic centimetres weighed 53 grammes, so that the total weight 
of the 654 cubic centimetres spawned would be about 619 grammes, cr 
223 grammes more than the loss of weight of the fish. 
In the other plaice (No. 5) 6:7 cubic centimetres of eggs weighed 6°65 
grammes, and the total weight of the whole quantity of 857 cubic centi- 
metres would be about 850 grammes, or 616 grammes in excess of the 
loss of weight of the fish. 
The difference is accounted for by the water secreted and absorbed 
as the eggs mature ; also, no doubt, by the absorption of water by the 
muscles and tissues of the fish after spawning, the increase of weight in 
No. 5 after the 9th May being probably due to this, since no food was 
eaten. 
When the first plaice (No. 2) was killed, on 9th May, the ovaries were 
found to contain a large quantity of spawn. When put into sea-water 
all went to the bottom within a few minutes, and the disc was chalky 
white, and in many cases wrinkled and irreguiar. They represent the 
eggs which the fish is unable to get rid of at the end of spawning, and 
which disintegrate and are absorbed. The quantity amounted to 43°95 
cubic centimetres, of which 3°75 cubic centimetres contained 1482 eggs, 
or 395:2 per cubic centimetre. The estimated number of eggs thus 
retained in the ovaries and destroyed was 17,369, or over 10 per cent. of 
the number spawned, which indicates a very considerable loss. 
The ovaries of the other plaice were in the same condition, slightly 
swollen, tumid, and soft. 
* [hid., p. 14. See also p. 145. 
