296 M. G. Winther on Races of 
Sound. One of them spawns in the spring, and corresponds 
in its habits so closely with other fish which are known to be 
stationary in the Sound, that in all probability it is stationary: 
likethem. This variety is the smallest of the three—a circum- 
stance which is in good keeping with the supposition that it 
does not at any time leave this comparatively narrow and 
shallow basin. The other two varieties are migratory, and 
visit the Sound during the autumn for the sake of spawning— 
one of them coming from the south, the other from the north, 
both meeting in that part of the Sound which les between 
the islands of Amager and Saltholm and the Swedish coast, 
and where a chain of shallows, intersected by winding chan- 
nels, stretches right across. The southern kind of herring 
agrees with Nilsson’s description of the “ Kiviksill” (in 
Skand. Fauna, Fiskar, p. 496) ; this is in all probability 
peculiar to the western part of the Baltic, which differs not a 
little from the portion beyond Bornholm as to the saltness of 
the water &c. Every autumn large quantities of these 
herrings travel as far as the Flinterende, a channel, well 
known to navigators, between Saltholm and the Swedish 
coast, where they spawn, and from which they again return 
to the Baltic in the winter. Sometimes, but rarely, easterly 
winds and strong currents carry them further north after the 
spawning-season ; but until then they do not ordinarily go 
beyond the Flinterende. 
The second of the two varieties which spawn in the autumn 
arrives in the Sound from the Kattegat, and is intermediate 
between the Kiviksill and the Kullasill of Nilsson, or ordinary 
herring of the Kattegat. On account of its habits, this variety 
is called Bundsild or bottom-herring. Generally speaking it 
is very regular in its habits, keeping quiet near the bottom of 
the sea in the daytime, moving about in the deep from about 
an hour before sunset till an hour after sunset, or even as late 
as midnight if the moon is high, and then rising to the sur- 
face, where it remains until sunrise; but in the spawning- 
season these herrings move about irregularly, and may be 
caught at any time. On their journeys they follow the 
deepest channels, allowing themselves to be carried along by 
the current, and in stormy weather regularly seeking the lee 
coast. The temperature of the water in the Sound in the 
spawning-season is from 50° to 53°6 Fahr. ‘The principal 
spawning-ground of this kind is on a submarine plateau north 
of the Flinterende. After the spawning they usually take a 
turn south into the bay of Kjége, and then return north- 
wards to the Kattegat. The most remarkable circumstance 
in connexion with them is the periodicity which has been ob- 
served in the take of them. Herring-periods are known in 
