of the Fishery Board for Scotland. 



193 



surface ; in the eighth the abrasion was considerable, but was beginning 

 to heal ; in the tenth the abrasion had healed except at one side, and the 

 fish was plump. 



Looking at the above facts alone, it might fairly be concluded that a 

 plaice of 10 or 11 inches in length, living in the sea under natural con- 

 ditions, grows at least 3 or 4 inches longer in the course of a year. 



The experiments in the tanks were begun in December 1891, and the 

 following Table shows the variations in length and weight at different 

 periods : — * 





No. 1. 



No. 2. 



No. 3. 



No. 4. 



Date. 































Length 



Weight 



Length 





Weight 



Length 





Weight 



Length 





Weight 





in 



in 



in 





m 





in 





in 





in 





in 





inches. 



lbs. oz. grs. 



inches. 



lbs. oz. grs. 



inches. 



lbs. oz. grs. 



inches. 



lbs. oz. grs 



1S92. 





























Jan. 14 



18| 



2 15A 0 



15f 



1 





0 





0 



15£ 



40 



13 



n 



13| 0 



„ 28 



19 







1 



e| 



60 











131 

 1U 



0 



13 30 



Feb. 11 





2 15i 0 





1 





0 











0 



13| 60 



„ 25 

 Mar. LO 





2 15 0 





1 



m 



0 





0 



15 



0 







14± 0 





2 15.i 40 





1 



71 



100 





0 



15 



40 



lk 



0 



May 5 







16 



1 



9f 



100 





0 



m 



0 



1) 



15| 60 



June 6 









1 



ioj 



0 





1 



0 



0 



13| 



1 



Of 0 



July 6 









l 



12 



0 



14! 



1 





60 



1 



1 0 



Aug. 6 









1 



lOf 



0 





1 



if 



0 





] 



OA 0 



Oct. 6 









1 





0 





1 



Of 



0 





1 



Of 0 



Nov. 6 









1 



8f 



0 





1 



0 



0 





1 



1 0 



Dec. 6 

















1 



OA 



50 





1 



1J 0 



1893. 



























Jan. 6 









1 



9 



0 





1 



o^ 



30 





1 



Of 30 



Feb. 6 









1 



10 



0 





1 



Of 



0 



13ft 



1 



U o 



-Mar. 6 









1 



lOf 



0 



14 § 



1 



If 



30 





1 



If 50 



April G 









1 



111 



0 





1 



2 



60 





1 



2 70 



May 6, 









1 



H 



t o 





1 



if 



0 





1 



2J 0 



* This fish (No. 1) was found dead on the 18th of March. It was much distended, and the 

 ovaries, which weighed 164 "2 grammes, contained ripe eggs. The temperature of the water in 

 the tanks was 10° C. ; that of the sea 9 5° C. 



t On 6th April the ovaries were much distended ; on 6th May they were partially spent. 



j On 1st February distension over the ovaries was considerable ; on 6th May they were very 

 large. 



A number of other plaice were similarly measured and weighed, but 

 the general results only need be given. Thus one was 12 J inches long, 

 and weighed 9 J oz. on 3rd December 1891 ; 13 inches and 11^ oz. on 

 25th February 1892 ; 13 T \ inches and 13J oz. on 5th May • 13J inches 

 and 14 J oz. on 6th September. From this date up to 6ch May 1893, its 

 length and weight remained the same. Another, which measured 12 

 inches and weighed 9f oz. on 28th January 1892, a week after being 

 placed in the tank, was 12§ inches and 13| oz. on 6th May 1893 ; a 

 third, at the same dates, was 12J inches and 12 J oz., and 12| inches and 

 a liitle over 12| oz. respectively. Specimens marked similarly to those 

 in the sea fell off in weight, or only increased by fits and starts. 

 The tanks in which these fish were kept were made of concrete, three 

 feet deep, and containing about 300 gallons ; there was an almost 

 constant circulation, and an abundant supply of food. The results are 

 somewhat puzzling; they at all events show, in conjunction with those 

 derived from the migration experiments, what a very important factor 

 confinement may be in interfering with normal growth, and the caution 

 necessary in drawing conclusions from such experiments. Cunningham, 

 who has worked at the subject more extensively than any one else, shows 

 the great variations in the rate of growth of flounders reared in captivity, 

 but he does not appear to have reared plaice, f 



* I am indebted to Mr Peter Jamieson for having measured and weighed the fish 

 on the dates given. 



t Vide this Naturalist's papers in the Journal of the Marine Bioloqical Assoc., 

 vol. ii. , Nos. 2, 3, and 4. 



