side of the body. In Central Europe, however, these shields generally disappear, I suppose through the absence of some dangerous enemy to whose attacks the little creature is habitually subject in our British waters. This last idea, however, must be accepted as purely theoretical for I can not suggest who that enemy may be. The three-spined stickleback is a very active and voracious little fellow, exceedingly destructive to the fry of carp or trout, and therefore, of course, highly detrimental in ponds where the preservation of larger fish is a matter of interest. It is scarcely to be conceived, says our great piscicultural authority, Dr. Günther, what damage these little creatures do, or how prejudicial they are to the increase of all the other fishes among whom they live. Their industry, sagacity, greediness, and success in seeking out and destroying all the young fry that come in their way are indeed simply marvelous. To take a single instance, a small three-spined stickleback kept in an aquarium devoured in five hours' time, by actual observation, seventy-four young dace, each a quarter of an inch long. Two days after, the same unconscionable little gourmand swallowed sixty-two, and seemed as hungry at the end of that bout as if he had never tasted breakfast. Considering that stickleback sometimes simply swarm in rivers, ascending them facto agmine in amazing shoals, the damage they are calculated to do to the trout and bream fishery can only be adequately known to Professor Huxley, who has long and truly urged that the number of fish caught or destroyed by man's will sinks into what the French scientists call une quantité négligeable by the side of the havoc everywhere wrought through the natural enemies of each species.
Our other native British fresh-water kinds are the nine-spined stickleback (commonly called the ten-spined out of pure cussedness) and the four-spined, also known as the smooth-tailed, though authorities differ much as to the division of species, some making many and some few. The nine-spined variety is a very small kind, more or less estuarine and semi-marine in his tastes, a frequenter of the river-banks about Southend and Chatham, and much given to migrating in shoals up the creeks and backwaters in early spring. He can also generally be discovered at the Ship or the Trafalgar during the fish-dinner season, trying to pass himself off in good company as a distinguished fish among a plateful of whitebait; but his imposture may be easily detected by observing the tiny stickles on his back, which are too small, indeed, to make him unpleasant eating, but quite big enough to prevent him from giving himself any aristocratic airs on the strength of his resemblance to a parliamentary delicacy. His sides are perfectly smooth and unprotected, and he may be investigated by the curious, nest and all, nearly everywhere among the brackish marshes of the Thames estuary.
The fifteen-spined stickleback or sea-adder is our one marine English species, common on many parts of the British coast, and specially
