318 



Part III — Twenty -fourth Annual Refori 



from 14mm. to 34mm. (^-lf inches), the modal size, or size of greatest 

 frequency, being 19mm., the mean 24mm., and the average 23*3mm., or 

 J of an inch. 



The collection seems to include more than members of one series, 

 however, the numbers under each millimetre being as follows : — 



14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 

 1253533 2 3541132222 2 -1 



The growth is thus very slow, the increments being as follow : — 



Date. 



Size. 



Increase. 



Days. 



Range. 



Average. 



21st October, 



Mm. 



14-20 



Mm. 

 17 



Mm. 





11th November, 



13-25 



19 



2 



21 



15th November, 



13-26 



19-5 



2-5 



25 



26th December, 



14-34 ? 

 [14-26 ? 



22-3 ? 

 20 



5-3 ? 

 3-0 



66 

 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 (^| 

 inch). The arrangement of the measurements under the various milli- 

 metres is as follows : — 



15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 

 1 2 2 6551623432315131 



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 205mm., and the average 

 20"4mm., or \^ 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 | of an inch. The arrange- 

 ment of the measurements of these two collections in millimetres is as 

 follows : — 



6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 



(2)--- - - - - - - - - 1 4 2 10 7 3 2 2 



(2) 3 - 1 16 17 7 3 1 - - - - - - - - - - - 



In the Forth collections, the next older series is represented by one 

 herring, 71mm, (2^| 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 



