Early Life-history of the Herring. 369 
I do not propose to enter here into any minute structural 
details. 
As is well known, all herrings do not spawn at the same 
time, some selecting the spring and others the autumn for 
that purpose. Professor M‘Intosh is of opinion that by far 
the greater number spawn in the spring; and this seems con- 
firmed, so far as regards this locality, by the greater abun- 
dance of young forms obtained here in that season. 
Mr. Brook (‘Fourth Annual Report Scotch Fishery 
Board’) gives January to March as the spring spawning- 
season, the time varying with the locality, Anstruther and 
Buckie being the earliest. 
The egg of the herring is demersal, differing thus from the 
pelagic egg of the sprat. The intraovarian development of 
the herring has been worked out by Kupffer and subsequently 
by Brook (3rd and 4th Ann. Rep. 8S. F. B.). 
Eggs were obtained here on Feb. 5, 1885, from Anstruther, 
and hatched out in the laboratory in twenty-five days. 
Newly hatched forms occurred on March 7, 1887, and 
Jarval and post-larval forms in March and the beginning of 
April in 1887 and 1889. 
The period of incubation varies with the temperature *. 
It is probably never less than three weeks in the early spring, 
but it may be barely a week in the autumn. ‘Thus, except in 
very early localities, young herrings cannot be expected before 
the beginning of March. In 1889 great numbers of young 
herrings were obtained, the first being early postlarval forms 
on March 22 and larval and postlarval on March 28. 
The newly hatched herring (figure 1), about =4 inch longt,, 
is in the larval condition f, 7. e. the yolk is still unabsorbed. 
The absorption of the yolk takes three or four days, when the 
* See Mr. Brook’s account of Meyer’s:experiments with regard to tem- 
perature, 3rd Annual Report Fishery Board for Scotland, 1884, p. 49.. 
+ Kupffer gives the length of the newly hatched Baltic herring at 5:2- 
5°3 millim. (38rd Ann. Rep. 8. F. B. 1884, p. 47). 
{ My. J. T. Cunningham gives a figure of a larval herring in Trans. R. 
S. E. vol. xxxi. pt. 1. It differs slightly from my own figure, 
