of the Fishery Board for Scotland. 



241 



About half the growth thus takes place during the few months in 

 summer, the growth in the 100 days being almost exactly the same as in 

 the remaining 265 days, which include the winter months. 



If the differences between the averages of the successive series are 

 considered, as in the following Table, it will be found that between the 

 first and second groups the differences vary from 5"24cm. to 9*98cm., and 

 the mean of this is 6-40cm., or 2| inches. It appears, however, to be a 

 trifle too high. The best collections, in which the series are most equally 

 represented at the different sizes, indicate a very slightly smaller rate of 

 growth. It may be said that the gurnard in the early generations grows 

 about 6"0cm., or 2|-2| inches, in a year. 



In the later generations growth is slower. In some of the collections 

 five or six series belonging to different years can be made out. 



In some large collections made during the spawning period, in Sinclair 

 Bay, Moray Firth, the sexes were determined and separately measured, 

 but the tables of measurements and the curves constructed on them did 

 not show the grouping very clearly. The clue furnished by the study of 

 the smaller collections above described enables the divisions between the 

 earlier seriss to be indicated, and it will be seen they agree with the 

 statements made as to the grouping and the rate of growth. These 

 collections from the northern part of the Moray Firth show that at least 

 eight or nine generations are present. 



GURNARD. 



Date and Place. 



Group 



No. 



Range of 

 Size. 



fference. 



Modal 

 Size. 



Mean 

 Cm. 



Arithmetic 

 Average. 



Approximate 

 Age. 



Apparent 

 Growth from 

 Preceding 







Cm 



5 



Cm. 



Inch. 



Years 



M'ths 



Series. 









Cm. 







Cm. 



Inch. 



Firth of Forth— 



























May 9-13, 1901, - 



I 



21 



7 9-13 1 



5-2 



9 



10-5 



10-11 



4 





11 









II. 



32 



14 0-19-1 



5-1 



16-5 



16 



1621 



6f 



1 



11 



61 



2& 





III. 



20 



19-6 24-1 



4-5 



21 



21-3 



21-54 



8J 



2 



11 



5-3 



2^ 





IV. 



14 



25-2 28-9 



37 



27 



26-5 



27-0 



lOf 



3 



11 



5-46 







v. 



13 



3 



29-7-32-5 

 34-3 



2-8 



30 



31 



30-97 



12} 



4 



11 



3-97 





July 23, 1901, - 



I. 



32 



11-0 13-7 



2-7 



12 5 



12-5 



[12-4 





1 



1 









II. 



107 



14-3 20-2 



5-9 



16-5 



17 



17-1 



6| 



2 



1 



[4-7 



w 





III. 



12 



21-0-26-5 



5-5 



22-5 



23-5 



23-3 



9 A 



3 



1 



6-2 





August 16-21,1901, - 





78 



10 -8-1 5 -6 



4-8 



13 



13 



13-14 



5J 



1 



1-2 









II. 



33 



16-4-22-6 



6 2 



20 



19 



19-26 



n 



2 



1-2 



6-12 





Aberdeen Bay — 



























July 5, 1901, 



I. 



109 



9-7-13-8 



41 



11-5-12 



12 



11-56 





1 











II. 



61 



14-2-19-9 



5-7 



17 



17 



16-90 



6? 



2 





5-34 





Q 



