of the Fishery Board for Scotland. 327 
On the 18th December, a collection of 410 herrings varied in size 
from 110mm. to 165mm. (4} to 64 inches), the range being thus 56mm. 
The mean was 137mm., the average 137°Dmm., and the mode 141mm. 
(a little over 54 inches). An examination of the millimetre table, or of 
the curve (Pl. X VII.) shows that there is in this case a slight fusion of 
two groups, and that the beginning of the large group is probably about 
ll‘5em. The 2-millimetre arrangement of the measurements is as 
follows— 
WOOO 2 1il-2 1184, 115-6 117-8 _-119-90 191-2 128-4 
1 3 1 3 5 8 9 17 
At the end of the series the 2-millimetre arrangement is this :— 
150-1 152-38 154-5 156-7 158-9 160 1 162-3 164-5 
11 12 3 4 3 4 ~ 1 
the mode being 141mm., the mean 137-5mm., and the computed average 
135°9mm. ‘The mode (5°; inches) probably best represents the group. 
hese herrings are spring herrings about 2 years and 8 or 9 months 
old ; those taken on the 17th appear to be the autumn series, about 2 
years and 3 or 4 months old, On the 29th December, 16 herrings were 
taken, from 108mm. to 154mm. 
A series of older herrings than these were caught in Aberdeen Bay in 
May and June, 1901 and 1903. 
On the 30th May, 1901, the collection numbered 601, ranging from 
142mm. to 228mm., and forming two series at least. ‘The first contained 
598 herrings, from 142mm. to 186mm. (53 to 72 inches), or it might be 
182mm. The modal size was 159mm. or 160mm., the mean 164mm., 
and the computed average 162mm., or 63 inches. These herrings are 
in their fourth year, and, judging from their position in relation to 
other series on the synthetic table, they are spring herrings, and thus a 
little over three years old. 
There were other three herrings, measuring respectively 196mm., 
207mm., and 228mm. (9 inches). 
Two collections were obtained in June. The first, on the 15th (1903), 
contained 557 herrings, and three series were present. The curve 
(Pl. XVII.) and the millimetre table show that the first great group is 
not pure, but is slightly mixed with the next group of larger herrings, 
represented on 30th May and on 28th June, and the measurements ex- 
tend from 118mm. to 182mm.,a range of 64mm., which is too large. 
The first series begins at 118mm., and apparently extends to 163mm. 
(46 to 6 inches), but it might go to 167mm. The 2mm. arrangement of 
the measurements at this part is as follows :— 
156-7 158-9 160-1 162-3 164-5 166-7 168-9 170-1 
19 V7 13 6 9 4 6 5 
The modal size of the group is 138mm. or 139mm. (54 inches), the mean 
is 140°5mm., and the computed average 141-8mm., or 52 inches. This 
group is thus about 2cm. (# inch) less than the group on 30th May, and 
I take it to represent autumn herrings in the fourth year, that is, which 
want about three months of being three years old. The group of 405 
spring herrings, taken in Aberdeen Bay on 18th December, above 
referred to, were of about the same age (2 years and 9 months) and of 
the same size as these. 
The spring herrings mixed with them number about 30, and range 
from about 164mm. to 182mm. There were also four herrings measur- 
ing 208mm., 223mm., 225mm., 234mm. 
On the 28th June, fifteen days later, but in 1901, 650 herrings were 
taken at Lunan Bay, a little further down the coast, in 123 fathoms, 
