OUR ECONOMIC SEA FISHES. 401 



third year it arrives at sexual maturity, say, twelve to fifteen 

 inches ; though growth continues thereafter, Plaice of thirty 

 inches being recorded. There appears to be a northern large 

 and southern small breed of Plaice, a circumstance confusing in 

 legislating on size limits for market purposes. Experiments by 

 the Scotch Fishery Board officials in St. Andrew's Bay and 

 Firth of Forth prove that the young Plaice travel in definite 

 directions. From seaward where let free a semi-rotary course 

 was followed by south shore westerly, then by north shore 

 easterly, towards their spawning grounds ; many specimens spent 

 a long time in traversing the route. This tallies with Holt's 

 observations on the opposite shore of the North Sea. There the 

 currents trend to the Heligoland bight, the ova floating in that 

 direction, where the post-larval fish spend a period, again to 

 return to the offshore spawning areas. Their chief food is 

 molluscs of various kinds and marine worms. 



The Sole has had a finely illustrated monograph devoted to it 

 by Cunningham (Mar. Biol. Assoc). In this its embryology, 

 adult structure, and economy are fully treated, and various species 

 of Solea meet descriptive notice. The egg, very characteristic, has 

 a ring of minute oil-drops and a segmented yolk. Incubation lasts 

 four to ten days. The larva is hardy and restless ; the post-larval 

 changes in the main resemble those of the Plaice. At nine 

 months it is two and half inches, a year old six or seven inches, 

 second year nine to eleven inches, and third year nine to fifteen 

 inches long. There is a migratory movement analogous to the 

 Plaice, but Soles seek the deep water during cold weather, and 

 vice versa. The Turbot, though not an abundant fish, would 

 seem prolific, judging from its one to ten million ova. Eggs 

 hatch in six or seven days. At their later stage these assume 

 quite a red appearance, and this pigment coloration is a marked 

 feature of the larva, though soon changing to orange hue. In 

 the post-larval stage the head has a spine armature, which after- 

 wards disappears. Few of the Turbot's pelagic ova are found 

 either offshore or inshore. It spawns offshore, where the larval 

 and post-larval stages are spent ; in their later youth they disport 

 themselves inshore, but when ten to eleven inches they again 

 seek the deep water. Its predacious Herring-feeding habits keep 

 it moving after these vagrant fish. The Brill spawns earlier than 



