THE THEORY OF TITTLEBATS. 837 



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 theoreti- 

 cal for I can not suggest who that enemy may be. The three-spined 

 btickleback 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. Giinther, 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 sim- 

 ply 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 tine quantite negligeable 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 stick- 

 leback (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 estua- 

 rine 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 dis- 

 covered 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 de- 

 tected by observing the tiny stickles on his back, which are too small, 

 indeed, to make him unpleasant eating, but quite big enough to pre- 

 vent 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 Eng- 

 lish species, common on many parts of the British coast, and specially 



