285 



to the north and west, 2 of the males and 2 of the females to the north and east, 

 1 male and 1 female to the south and west, and 2 females to the south and east. 



^ to 100 miles. — Three, or 6-1 per cent., were found within these limits, 2 males 

 (8"7 per cent.), with an average of 74 '25 miles, and 1 female (3-8 per Cent.), which 

 went 63 '5 miles. The female and one of the m.ales were found on the north coast 

 to the north and west, and 1 male to the south and east, off Tod Head. 



Maturity. 



Males. — The condition of the testes was ascertained in 16 of the 27 recaptured. 

 Two were " spawning," both taken in February 1913, to the north and west, 1 at 

 44 and the other at 24 miles distant. Seven were described as " ripe," 1 caught 

 in January 1913, on the north coast, off Dunnet Head, at a distance of 60| miles 

 to the north and west ; 2 in February 1913, 32 miles and 42 miles to the north 

 and west ; 1 in March 1913, 40 miles to the north and west ; 1 in April 1913, 

 14 miles to the north and east, 1 in February 1914, 38 miles to the north and west, 

 and one in November 1912, 27 miles to the north and west. Three were said to be 

 " nearly ripe," all taken to the north and east, 1 in October, at a distance of 11 miles, 

 1 in November, at 20 miles, and 1 in December 1912, at a distance of 16 miles. 



Females. — Of the 28 females recaptured, the condition of the ovaries was 

 recorded only for 12. One was described as " ripe " ; it was taken in August 1913, 



14 miles to the north and west. One was " spent " ; it was taken in April 1913, 

 11| miles to the north and east. Seven were "nearly ripe " ; 3 were found in 

 October 1912, at 11, 18, and 29 miles to the north and east ; 3 were recovered in 

 November 1912, 1 at 14 miles north and east, 1 at 28 miles to the north and west, 

 and 1 at 32 miles to the south and east ; 1 was recaptured in December 1912, 



15 miles to the north and east. 



EXPERIMENT VII. 



2lst November 1912. 



In this experiment, 51 plaice, viz. 26 males, 24 females, and 1 of unknown sex, 

 were marked and liberated at 58° 10' N.; 2° 35' W. The males measured from 22 

 to 39'5 cm., and 9 were under adult size on liberation ; the females ranged from 

 24-5 to 46 cm., and 17 were under adult size when liberated. 



The numbers liberated and recaptured, arranged in 5-cm. groups, are as 

 follows : — 



The fish used in the experiment were trawled by the " Goldseeker " in the 

 Dornoch Firth on the 21st November, and were liberated later on the same day. 



The number recaptured was 27, or 52-9 per cent., viz. 15 males (57-7 per cent.) 

 and 12 females (50 per cent.). All the males recaptured were of adult size, ranging 

 from 33-3 to 44-6 cm., and averaging 37-3 cm., as against a range of from 25'5 to 

 39-5 cm. and an average of 34-6 cm. on liberation ; they were at liberty for from 

 to 830 days, the mean being 194 days ; they travelled distances of from 11 to 58 

 miles, the average being 27-7 miles, and the mean rate 1*4 miles. Six of the females 

 were of adult size on recapture, averaging 41-2 cm., as against 38-6 cm. on libera- 

 tion ; they were at liberty for a mean period of 218 days, and migrated distances 

 of from 12^ to 49^ miles, at a mean rate of 1-6 miles. Six were under adult size, 

 averaging 32-5 cm., against 32-1 cm. ; they were free for a mean period of 120 

 days, and moved from 8 to 45 miles, the average being 22-2 miles, and the mean 

 rate 19 miles. 



