Page:The Zoologist, 4th series, vol 1 (1897).djvu/427

Rh be found equally abundant in both. According to Mcintosh Sprats spawn well up reaches in estuaries, but Cunningham avers that spawning occurs in the deep water. From such data it may be inferred that they have a summer and winter spawning season in different areas like the Herring. Yet there are manifest physical differences in their entire career. In the Sprat the female but carries 5400 ova; the eggs are pelagic, though inclining ground wards, and they are markedly reticulate; incubation short, three to four days; a slower larval and post-larval development; at the early stage mouth closed and absence of pigment in eyes and body generally; transformation at 1¼ in., about a year old 2 in. or 3 in., and the sexually mature stage 4 in. to 4½ in. long, viz. two years of age.

The Pilchard essentially is only a south-west British form, and its winter home the English Channel. They are rarely caught in the gravid condition; their ova count some 60,000. They spawn far off shore. The egg is typical of those that float, but unique in possessing a large egg-membrane space, a segmented yolk, and an oil-globule—these three characters not being united in Clupeoids or other families. Incubation takes four or five days. The early larva is one-seventh of an inch long, the yolk still large, the mouth closed, and pigmentation sparse. At three days the mouth develops, at five days they feed, are one-fifth of an inch long, and the yolk absorbed. At the Sardine stage, four inches or over long, they are about one year old, and they are sexually mature at two years of age, then being eight or nine inches long. The Anchovy is also chiefly a southern British form, and for it there is no regular fishery; but that of Holland, on the contrary, is very valuable. Cunningham infers that the Dutch Anchovies retreat in October towards the English Channel, the same again migrating north in the spring to spawn. Their sausage-shaped egg is quite exceptional among floating eggs. The Shads have the Salmon habit of running right into fresh-water streams, where they spawn. They are less a food product in this country than in America, where Shad hatcheries are quite in vogue.

The Pleuronectidæ, or flat-fishes, nowadays holds a high position in the English fish-trade. Not being used in the salted condition, formerly their consumption was restricted coastwise;