Maturity. 



Males. — Of the 24 recaptured, the condition of the testes was recorded for 18. 



One was " spawning " ; it was taken in March 1914, off Clythness, at a distance 

 of 64 miles to the north and west. 



Two were " nearly ripe," 1 taken in January 1913, oS Banff, 36| miles to the 

 north and west, the other in January 1914, 41 miles to the south and west, in the 

 offshore waters. One was described as " three-quarters ripe " ; it had gone 18 

 miles to the south and west, in November 1912. 



Among those of adult size, whose testes were described as " immature," 2 were 

 taken within the hmits of the spawning season, 1 in February 1913, 11^ miles to 

 the south and west, the other in April 1913, off Tarbet Ness, Moray Firth, at a 

 distance of 74 miles to the north and west. Among the males under adult size 

 (33 cm.) was 1 measuring 31-32 '8 cm., taken in the Moray Firth off Lossiemouth, in 

 January 1913 ; it was described as " nearly ripe." 



Females. — Of the 28 taken, the condition of the ovaries was ascertained in 27 

 cases. 



None was described as " ripe " or " nearly ripe," but 1, " apparently spent," 

 and measuring 36-5-39"7 cm., was taken in May 1913, off Foula, 141 miles to the 

 northward. 



Among those of adult size whose reproductive organs were " immature," were 

 4 taken within the limits of the spawning season, 1 in January 1913, measuring 

 39-40 cm-, in the Moray Firth, off Macduff ; 2 in February 1913, measuring re- 

 spectively 37-39-8 cm., and 33 "5-38 "5 cm., which were taken inshore, near Rattray 

 Head, at distances of 11 and 13 miles to the north and west ; the fourth, which 

 measured 35 •5-36-1 cm., was captured in January 1914, after 563 days, 28 miles 

 to the south and west. 



Experiments at Smith Bank, Moray Firth. 



Ten experiments were made at Smith Bank, in the Moray Firth, or its immediate 

 vicinity, extending from February 1911 to November 1913, the particulars being 

 given in the accompanying table : — 



The total number of plaice marked and liberated was 707, comprising 296 males, 

 240 females, and 9 whose sexes were not ascertained. The total number recaptured 

 was 336, or 47 4 per cent., of which 148 (50 per cent.) were males, 184 (45*7 per cent.) 

 were females, and 4 (44-4 per cent.) were of unknown sex. 



EXPERIMENT I. 



\Uh February 1912. 



In this experiment, 42 plaice, consisting of 21 males and 21 females, were marked 

 and Uberated at the position 58° 10' 30" N.; 2° 55' 30" W., in a depth of 20 fathoms, 



