22 AUGUST 1931, Page 19

" The Finny Subject of the Sea "

A History of Fishes. By J. R. Norman. (Beim. 28s.)

WHEN the Third Fisherman in Pericles threw out the query, " Master, I marvel how the fishes live in the sea," he was answered : " Why, as men do a-land ; the great ones eat up the little ones." Which is true to an extent ; but Mr. Norman has a much more comprehensive answer to give to the question than that. To questions, indeed, he, as a Keeper in the- Zoological Department of the British Museum, is very well used, and he mentions how in the course of his work he is bombarded by the enquiring public with interrogatories like " How fast does a fish swim ? How many fishes are there in the sea ? Where did fishes first come from ? To what age does the average fish live ? Can a fish think, or feel pain ? (a favourite query from the angler !). What is Rock Salmon ? " (which on page 885 he tells us is the Cat-fish, though in Scotland the Coal-fish is sometimes so known). It is, in the hope of satisfying this more or less intelligent curiosity, and generally of expounding " each secret fishy hope or fear," and of illustrating every facet of fish life and development, that he has written his almost omniscient and wholly fascinating book. The work of a scientific expert and therefore dependable in every particular, it is written in a style so devoid of technical terms that it comes well within the scope of that vague creature known as the general reader and of every lover of wild life. Instruction there is here in fullest measure but never tediously obtruded, and also a very special charm of description which sets out for us not only " the finny subject of the sea," but the history of fresh-water fishes as well.

What is a fish? A Whale is not a fish, for he has vestigial hairs on his muzzle, his lady suckles her young and clasps them lovingly with a flipper, the bones of which almost exactly resemble the human hand. Mr. Norman defines a fish " as a vertebrate adapted for a purely aquatic life, propelling and balancing itself by means of fins, and obtaining oxygen from the water for breathing purposes by means of gills." In the matter of locomotion most people will be surprised to hear (a little contrary perhaps to the definition just given) that the fins are auxiliary merely, and not the fish's principal locomotory resource. The swift-darting Mackerel " depends almost entirely on body movements," which are operated by myomeres or muscle-masses arranged in pairs and running along either side of the body. Both he and other fish are also assisted " by the action of jets of water expelled from the gill-openings." The Mackerel does not twist his tail like the screw of a steamer ; indeed, with him, as with other fishes, " the part played by the tail in producing a forward thrust is far less important than was previously supposed." Then comes the question, much debated by anglers, " Can fish hear ? " The answer given by the author is " that the sense of hearing, if developed at all, is far from

acute, and may be largely confined to the perception of disturbances in the water." (The late Hely Hutchinson Almond, the famous Head-Master of Loretto School, used to throw large stones into a salmon-pool if the fish were at all dour about rising ; they at all events must have been fully conscious of " disturbances in the water.") And so Mr. Norman goes on telling us all about fish-economy, breeding, migration and development, laying always special stress on the evolutionary aspect of fish-life, how that both their bodies and habits have been modified to suit their surroundings or predilections. Thus flatfish, like the turbot, start life as ordinary round fish—with an eye on each side of the head. But the turbot, who likes to lie flat on the sea-floor, modifies one of its sides into what seems like a white belly, colours the other side to look like shingle, and shifts both eyes to the top of his head. The author hopes that his book may be found " a storehouse of facts." It is, indeed, and Mr. Norman is the happiest possible exhibitor of his specimens.

A storehouse, too, of fish-oddities, that would almost be unbelievable were it not that science vouches for every one There are those who have had the misfortune to get their fingers into a pike's mouth, but the pike cannot begin even to compare with the South American piraya, a shoal of which ferocious little fish has been known to kill and com- pletely tear the flesh off a horse and his rider. There are several sorts of fishes which can give a disabling electric shock ; many, like the common Weever of British seas, whose poisonous spines can inflict a dangerous wound ; one species of fish swims upside down and another standing on its tail. The Barracuda with dagger-like teeth herds shoals of other fishes into the shallows, and keeps them there ready for his next meal. The Archer-fish, which feeds on flies, brings its prey down by squirting a mouthful of water on it as it hovers over the surface. Our British Tench, as is well known, spends the winter buried in mud, which is at all events wet, but the African Lungfish can exist in dry mud, into which it creeps while wet and in which it hollows out a kind of cocoon oiled by a secretion of its own slime. One could go on indefinitely detailing the curiosities described in this absorbingly interesting book, but the inexorable limitations of space forbid more than to say that it ends with chapters on fishes in relation to human economy, and on fish-myths and legends—that of the sea-serpent among them. Mr. Norman does not exclude the possibility of the existence of such a creature, but notes also the possibilities of alcoholic vision. Meantime the Ribbon-fish, which may grow to more than fifty feet in length, ought to be good enough for us.

The book is made additionally valuable by the admirably explanatory illustrations of Lieut.-Colonel W. P. C. Tenison. M. J. C. M.