Page:The Zoologist, 4th series, vol 1 (1897).djvu/423

Rh The contents of the aforesaid Food Fish volumes are ostensibly identical, but their treatment somewhat dissimilar. That from St. Andrews is illustrated by twenty-one coloured plates containing some 250 figures, besides forty-five woodcuts distributed in the text. These represent the eggs, larval and post-larval conditions of the great bulk of our food-fishes. That from Plymouth has 159 woodcuts, and two maps of the fishing grounds of the British Islands and west coast of Europe. The authors freely acknowledge their indebtedness to the many workers of all countries. Besides other subsidiary matter the text deals with the pelagic fauna generally, egg development, and subsequent growth of the larvæ to adolescence onwards; but the major portion is devoted to the life-history of particular families and species of Sea Fish used for consumption. All the dry reading on synonymy and the opinions of the early classical or ichthyological writers are dispensed with. Both are excellent epitomes of the methods and results of modern research as adapted to the practical issue of fisheries questions.

No longer is the fish described from a shrivelled or spirit-preserved specimen. Rather is it now studied in the living condition in the aquarium in large tanks, or it is hunted out in its native haunts at all seasons, and frequently even in inclement weather there and then watched and examined in every stage as to age, condition, food, and surroundings. The eggs themselves are fertilized and hatched under the eye of the observer, and from the transparency of the pelagic ova, under the microscope and reagents, every change from fertilization to final hatching can be followed step by step with ease. Thereafter the post-larval changes and habits to adolescence are noted and compared with those of the adults at freedom in the sea.

While it could have been said with some show of propriety in the early eighties that none or very few indeed of our commercial sea-fishes' life-histories were known, now at least it may be affirmed that the great majority of them are tolerably well ascertained. For instance, of the Gadidæ, take the Cod as being that whose pelagic ova first attracted Sars' attention, and which have since undergone the close scrutiny of several able naturalists. It spawns from February till May, the female carrying from two to nine million ova. These diminutive glassy