196 Part III. — Eighteenth Annual Report 



2. Females. 



Region. 



Condition 

 of Repro- 

 ductive 



Size in Millimetres. 





Organs. 



240-260 



260-280 



280-300 



300-320 



320-340 



340-360 



360-380 



Heligo- 

 land 



Immature 

 Mature 



16 

 \ 



7 



o 



2 



o 



6 

 4 



10 



19 



2 

 13 



0 

 10 



Helder 



Immature 



14 



21 



17 



10 



0 



0 



0 





Mature 



\ 



o 



3 



4 



i 

 l 



3 



2 



Lowestoft 



Immature 



1 



8 



16 



14 



5 



1 



0 





Mature 



o 



o 



2 



3 



4 



4 



2 



Grimsby 



Immature 



1 



1 



4 



5 



5 



3 



1 





Mature 



0 



0 



0 



3 



6 



6 



o 



o 



i oiai 



Immature 



32 



37 



39 



35 



20 



6 



1 



(269) 



Mature 



2 



0 



5 



14 



30 



26 



22 



Do. inper- 

 centage 



Immature 

 Mature 



94 



6 



100 

 0 



89 

 11 



71 



29 



40 

 60 



19 

 81 



4 

 96 



From the first Ta.ble, which gives the proportions of the immature and 

 mature male specimens, those from Heligoland are omitted, because there 

 were very few specimens, and some doubtfully mature amongst them. It 

 will be seen from the percentage columns that the relative numbers in the 

 different divisions are more evenly distributed than they were in the case 

 of the data given by Cunningham, and the resulting curves are 

 therefore more uniform. 



A certain allowance should be made for growth, because the specimens 

 were not all collected at the same time. Those from Heligoland were 

 obtained mostly during October, those from Helder towards the end of 

 November, and those from Lowestoft and Grimsby during the spawning 

 season in January, February, and March. No correction is required for 

 the last, but those from Helder are at least two months from the height 

 of the spawning season, and those from Heligoland four months. The 

 average rate of growth yearly has been calculated for the earlier periods 

 by Cunningham,* Petersen,! Masterman,J and more recently by 

 Dannevig,§ and although there are considerable differences in their results, 

 yet it is allowable to conclude that for the stage in question the plaice 

 grow from 2-3in. (50-76mm.) in a year. The correction to be made 



* Cunningham, J. C. Jour. Mar. Biol. Ass., Vol. II., 1891-92. 

 f Petersen, C. G. J. Fourth Rep. of the Vanish Biol. Station, 1893. 

 J Masterman, A. T. Thirteenth Rep., Scot. Fish. Board, 1895. 

 § Dannevig, H. /Seventeenth Rep., Scot. Fish. Board, pp. 232-246. 



