318 Part III.—Twenty-fourth Annual Report 
from 14mm. to 34mm. (,°;-1% inches), the modal size, or size of greatest 
frequency, being 19mm., the mean 24mm., and the average 23°3mm., or 
T of an inch. 
The collection seems to include more than members of one series, 
however, the numbers under each millimetre being as follows :— 
14.515 16-17 18 19).:20".21 =22)) 2324) 25) (26, 27) 28-2930 Si) 32 ean 84 
Lo 22) 85 FSS PSBICSL P28" Seo rae eS DROS ae ee 
The growth is thus very slow, the increments being as follow :— 
| Size. 
Date. Increase. Days. 
Range. | Average. 
fee briny Mm. Mm. 
21st October, ... Lf AS 1)° 714-20 17 
lith Novembery © 20!) feerg ee) IS On ees 2 21 
| 
15th November, ie oe te, [2 LB=26 19°5 20 25 
26th December, an abe .. | 14-84? 22°32 5:3 2 66 
| [14-26 ? 20 o0he 66] 
| 
The sizes, it will be seen, agree very well with the post-larval herrings 
from Aberdeen Bay at corresponding periods. 
For the reason stated, it is probable that the average, and therefore 
the amount of growth in the December series, is too large. 
Near Burghead Bay, on 29th December, 1903, 56 post-larval clupeoids, 
measuring from 15mm. to 33mm., were taken, the modal size being 
20mm., the mean 24mm., and the arithmetical average 23-3mm (4? 
inch). The arrangement of the measurements under the various milli- 
metres is as follows :— 
To AG Ay 18) 19) 20) 20 22) 23 24 25) 26) 270 2829) 0 olan 
12 2 RO 5 SIS 62 y Sieea oS Se an Op von ee 
There are some reasons to suspect that these clupeoids may be sprats ; the 
diagnosis is therefore uncertain. 
On May 28, a compact series, numbering 31 specimens, and 
measuring from 17mm. to 24mm. were taken in the Firth of Forth. 
The modal size was 20mm., the mean was 20°'5mm., and the average 
20'4mm., or +2 of an inch. These represent the spring herrings, 
approximately two months old. 
The autumn herrings are represented by a collection taken at the 
mouth of the Forth on 4th September, in the same year. There were 
48, measuring from 6mm. to 13mm., the modal size being 10mm., the 
mean 9mm., and the average 9°7mm., or 3 of aninch. ‘The arrange- 
ment of the measurements of these two collections in millimetres is as 
follows :— 
= eS See aS ee oe tye ee SLO yy home ee 
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 
6.17 cere. atl Cyr ae te et SL igs 
In the Forth collections, the next older series is represented by one 
herring, 71mm, (2+3 inches) long, taken on 9th May, and by one of 
85mm., caught on 19th June. 
In some collections from the Firth of Clyde, the series is well 
indicated. Thus, on 17th October, the shrimp-trawl, working in from 
