Page:The Zoologist, 4th series, vol 1 (1897).djvu/429

Rh 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 versâ. 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 afterwards 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