872 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



The net is small enough to capture larval cod, but they are not a conspicuous feature, 

 very few having been seen, and the intermediate stages between the larval form and the 

 post-larval are difficult to obtain. The latter apparently tend shorewards in the end of 

 April, not at the surface, but in the deeper parts of the water, many, indeed, being by 

 and by caught on the bottom by a fine trawl-net. They sport about amongst the tangle- 

 forests and shallow water and neighbourhood, and as they get older seek the deeper 

 parts near the rocks.* They then, as Saks says, form shoals in deep water on the various 

 fishing banks, large numbers being caught the following summer both by liners and 

 trawlers. 



That a migration occurs in other Gadidse is apparent when we consider the case of 

 the ling. As a rule, the old ling frequents the deeper parts, yet the young, ranging from 

 5 inches upward, are plentiful off the Pier Rocks at St Andrews, especially in their barred 

 or tesselated condition. The post-larval haddock also would appear to frequent the 

 deeper water, as also does the post-larval whiting, the latter occurring in considerable 

 numbers south-east of the Island of May, and at a later period than the post-larval cod. 

 When older, viz., from 3 to 6 inches, they are not uncommon in St Andrews Bay at low 

 water. The larval frog-fishes and other types follow the same habits. 



On the other hand, some of the ordinary Pleuronectidse, e.g., the flounder, take a 

 somewhat different course. The larval forms are pelagic on the sites t frequented by the 

 adults, and then they gradually seek the bottom as well as the tidal margin, especially 

 the mouths of streams, in May, June, July, and August. They may be found in lessened 

 numbers there till well grown, so that the migration of this form is slight. The young 

 plaice appears to follow similar habits, but the large adults seek the deeper water off 

 shore. The same may be said of the turbot, the brill, and the long rough dab. The 

 larval forms of the craig-fluke (Pleuronectes cynoglossus) frequent the ground occupied 

 by the adults, and various stages may be secured by the same haul of the net. On the 

 whole, then, the evidences of migration relate only to the passage in certain species of the 

 post-larval stage to the shallower water, and the tendency of all the healthy larger forms 

 to seek the deeper water. The latter feature, for instance, is observed in the halibut. 

 It is apparent, however, that certain flat fishes, e.g., the "witch" or craig-fluke, so far as 

 at present ascertained, are confined for the most part to the deeper water and soft ground, 

 both in their adult and their younger stages ; and Miiller's topknot, the lemon dab (to some 

 extent), and others probably agree with them in this respect. It appears to be a feature 

 of moment that the post-larval forms of such as the " witch " and long rough dab swim 

 somewhat longer on edge — that is, are larger fishes with great depth of body before the 

 eye travels round, and before settling on the bottom. The post-larval stages of the 

 flounders and plaice appear generally in April, and are about half an inch or less in length, 

 their eyes as a rule being lateral in position; and as the season advances the left eye 

 moves forward a little, and approaches the dorsal edge. They vary considerably in size 

 at a given time, but not so much as the " witches " formerly alluded to, and would 



* Vide No. 104, p. 309. + Generally inshore. 



