254 THE ZOOLOGIST. 



have dealt with Cod. The Germans and the Dutch, again, 

 joined in marking Plaice in the international work. The Ply- 

 mouth naturalists, then, labelled a number of Plaice, returned 

 them to the sea, and founded on the numbers of those sub- 

 sequently captured several important conclusions, viz. (1) the 

 migrations of the species, (2) the rate of growth, and (3) the in- 

 tensity of fishing. 



In regard to the first head, viz. — the migrations — one Plaice 

 travelled 175 miles and another 210 miles in three months, 

 and Dr. Garstang considered that there was a general tendency 

 to move from the small fish-grounds of Holland to deeper water in 

 summer, and of those in the southern bight of the North Sea to 

 move northwards. Of those below 9^ in. most remained on the 

 spot in winter, migrating offshore in a north-westerly direction 

 the following summer ; whereas fishes exceeding that size 

 migrated southwards and westwards shortly after liberation. 

 Dr. Bolau, the German experimenter, differs from Dr. Garstang, 

 the former stating that Plaice leave the coasts in summer and 

 autumn, and return in spring, whereas the latter gives spring 

 and summer as the period for migration to the offshore. Here, 

 then, is considerable variation in the results, and neither agrees 

 with the condition at St. Andrews. Moreover, it may be that the 

 irritation of the label may have had something to do both with 

 the capture and the migration of some of the marked Plaice, for 

 the wound made by the transfixing wire is often irritable, is in 

 contact with bone, and may be felt by the fish when skimming 

 over or into the surface of the sand. Besides, some of the cap- 

 tured fishes were not well-nourished. If the white surface of the 

 flat-fishes could be tattooed, such would be a great improvement 

 on the present rough method, which even in the hands of a skilful 

 operator leaves a source of constant irritation, and a permanent 

 lesion. I have no doubt that Sir James Dewar could readily suggest 

 an indelible and comparatively innocuous colour for this purpose.* 

 The migrations of these marked Plaice and other forms, however, 

 are interesting in connection with the distribution of the species 

 and their general safety. The data are as yet too few, as Dr. 



* Sir James recommends the carbonaceous or Indian ink process. Experi- 

 ments will shortly be carried out at St. Andrews. An instrument with nume- 

 rous points would probably carry out the work quickly. 



