246 



Maturity. 



Males. — The condition of the testes was ascertained in 10 of the 16 recaptured. 

 Three were " spawning," 1 taken in February 1913, off Aberdeen, 126 miles to 

 the south and west, another in March 1913, near the same place, at a distance 

 of 119 miles, the third in March 1914, in the Moray Firth, near Clyth Ness, 93 

 miles to the south and west. One was described as " ripe " ; it was recovered 

 in February 1913, 16 miles to the south and west. One was " spent " ; it was 

 got in May 1913, 13 miles to the north and west. Two were "nearly ripe," 1 

 captured in December 1912, 44 miles to the south and west, and 1 in January 



1913, south-east of Noss Head, in the Moray Firth, at a distance of 76 miles. 

 Females. — The condition of the ovaries was recorded in 13 of the 15 recaptured. 



None was "spawning," but 1 was "ripe " ; it was captured on 19th August 1913, 

 at Smith Bank, Moray Firth, 89 miles to the south and west. Three were de- 

 scribed as "spent," 1 taken in March 1914, south-east of Noss Head, in the Moray 

 Firth, 76 miles to the south and west, another in April 1914, near Buchanness, 

 114 miles to the south and west, and the third in May 1914, 35 miles to the south 

 and west, to the east of the Orkneys. Among the females described as " imma- 

 ture," was 1, taken in March 1913, 79 miles to the eastwards, offshore, and it 

 measured 39-39-4 cm., and another, measuring 35-44 '7 cm., taken in January 



1914. 9 miles to the north and west. 



Experiments at 100 Miles East of the Isle of May. 



At this station, which lies in Lat. 56° 40' N. ; Long. 1° 21' E., with a depth of 

 water of between 40 and 50 fathoms, marked plaice were liberated on 2 occasions, 

 namely, in June 1912 and June 1913. Particulars in regard to the liberated fish, 

 and those recaptured, are as follows : — 



EXPERIMENT I. 



12iA June 1912. 



In this experiment, 91 plaice were marked, namely, 39 males, 47 females, and 

 5 whose sexes were not determined. The sizes of the males, on liberation, ranged 

 from 26 '5 to 38 cm., and 19 were under adult size ; the sizes of the females 

 varied from 27 to 54 cm., and 35 were under the adult size. The numbers 

 liberated and recaptured, arranged in 5-cm. groups, are set forth in the following 

 table : — 



