6983 plaice were marked with the vulcanite marks, and 3706, or 53* 1 per cent., 

 were returned, showing that the latter method was much the more satisfactory. 

 The number marked with the two vulcanite discs was 5637, and the number 

 recaptured was 3086, or 54-7 per cent. The number marked with the vulcanite 

 studs was 1346, and the number recaptured was 620, or 46-1 per cent. The 

 latter method of marking is thus not so satisfactory as that in which two discs 

 are used, connected by a silver wire. 



The fish, aitei being marked, were kept on board the "Goldseeker" in tubs of 

 water until they were liberated, the interval, in some cases, extending over a day 

 or more. The sexes were ascertained by holding the fish up to the light, the ovaries 

 being thus detected in the females. Comparatively few errors were made in deter- 

 mining the sexes by this method. 



The Interval between Liberation and Eecapture. 



The duration of the periods of liberty of the marked plaice, before th^y were 

 recaptured, varied very much. In a few cases, they were taken on the same day on 

 which they were set free ; in other instances, some years elapsed before they were 

 caught. In the following table, the recaptures in each period of three months after 

 liberation tor all the experiments, have been tabulated, the particulars for the 

 sexes being also shown separately, and percentages given : — 



It will be observed that the largest number was recaptured within three months of 

 liberation, and that the number caught in each succeeding quarter was less than 

 in the preceding quarter. Within the first twelve months of liberation, 2763, or 

 74"5 per cent., were taken ; in the second year, the number was 732, or 22'4 per 

 cent. ; in the third year, it was 179, or 4*8 per cent. , in the fourth year, 27, or -7 

 per cent. ; in the fifth yeai, 5, or "01 per cent. ; while one fish, a male, was taken in 

 the sixth year after liberation, having been at hberty 1821 days. 



[Table. 



