of the Fishery Board for Scotland. 



69 



comparatively little light entered was selected for the ripest and most 

 vigorous herring. In about half an hour after they were introduced we 

 noticed a large full herring moving slowly about the bottom of the tank, 

 and thinking it had suffered during the journey, I introduced a landing- 

 net, in order to remove it, when, much to my surprise, it darted to the 

 opposite end of the tank. I, however, without much difficulty, secured 

 the herring, and having ascertained it was a perfectly ripe female, again 

 set it free. In a few minutes I noticed her moving slowly quite close to 

 the bottom of the tank, with four other fish making circles around her at 

 some distance from the bottom. Appearing satisfied with some stones 

 which she had been examining, she halted over them, and remained 

 stationary for a few minutes about half an inch from their surface, the 

 tail being in a straight line with the trunk and the pectoral fins near or 

 resting on the bottom. While in this position, a thin beaded ribbon was 

 seen escaping from the genital opening to fall in graceful curves on 

 the surface of the stones so as to form a slightly conical mass, almost 

 identical with a cluster of ova on one of the stones dredged at Ballantrae. 

 As the little heap of eggs increased, some falling to the left side one 

 moment, while others fell to the right the next, according to the currents 

 in the water, the males continued circling round her at various distances, 

 while the other females in the tank remained apart. The males remained 

 from 8 to 10 inches above the bottom of the tank and formed circles 

 ranging from 18 inches to 30 inches in diameter. Some of the males 

 were swimming from right to left, others from left to right, and although 

 there was no darting about, no struggling among themselves (there is 

 nothing about the structure of the herring that suggests struggling), no 

 great excitement, there was a peculiar jerking of the tail as they per- 

 formed their revolutions. Soon the object of this peculiar movement was 

 sufficiently evident. Three or four times during each revolution each 

 fish expelled a small white ribbon of milt, which varied from half an inch 

 to three-quarters of an inch in length, and was nearly a line in breadth 

 across the centre, but pointed at both ends, and somewhat thinner than 

 it was broad. The delicate ribbons slowly fell through the water, some- 

 times reaching the bottom almost undiminished in size, but in most 

 instances they had almost completely dispersed before reaching the 

 bottom. In this way the whole of the water about the female became of 

 a very faint milky colour, and practically every drop of it was charged 

 with sperms, as was afterwards ascertained. It will thus be seen that 

 there is no attempt whatever on the part of the males to fertilise the eggs 

 as they escape from the female. While the female is depositing eggs at 

 the bottom the males concern themselves with fertilising the water in the 

 neighbourhood, and it will be observed that the males are careful to 

 guard against the influence of currents. By forming circles around 

 the female, and shedding milt on the way, it matters not how the 

 currents are running, they are sure to carry some of the milt towards 

 the eggs — the milt, like the eggs, sinking, though, not adhering to the 

 bottom. 



When the female had deposited a certain number of eggs at any given 

 spot, she moved forward in a somewhat jerky fashion without rising 

 from the bottom, and as she changed her position the males changed 

 theirs, so that the female was always surrounded by a fine rain of short 

 sperm ribbons. A specimen of hydrallmannia (PI. VII.) sent from Eye- 

 mouth, seems to indicate that the female moves about amongst sea-firs and 

 sea-weeds in exactly the same way as she does amongst stones. On each 

 stem of the colony there is a cluster of ova about the size of a small grape, 

 and all the clusters had reached, on arrival, the same stage of development 

 as if they had been deposited about the same time and by the same fish. 



