216 THE HOPLOSTETHUS. 



little creatures, and I am told by an angler fiiend that they destroy quantities of the spawn 

 of other lisli, and seize upon the young as soon as they are hatched. He also informs me that 

 they are extremely capricious in theii* choice of locality. For examj^le, at the head of a mill- 

 stream they may he found by thousands, while at the tail of the same stream not a single 

 Stickleback can be found. There are parts of rivers where they are so plentiful that the fisher 

 is entirely baffled in his sport by these little creatures eating his bait before it sinks to its full 

 depth, while the middle of the stream might be quite free from them. 



The Ten-spined Stickleback does not like salt water, and cannot be acclimatized to the 

 marine aquarium like its three-spined relative. All the Sticklebacks are remarkable for the 

 comparative nakedness of the skin, which for the most part bears no scales, as in the gener- 

 ality of fish, and in the Ten-sjiined species is wholly naked. The place of the scales is sup- 

 plied by certain bony or scaly plates upon the side, and it is the nakedness of the skin which 

 permits the colors of these little fish to glow Avith such bright and changeful hues. 



The color of this species is green upon the back, and on the abdomen and sides silvery- 

 white spotted minutely with black. The fins are very slightly tinged with yellow. The length 

 of the Ten-spined Stickleback is variable, but rarely exceeds two inches. 



The FiFTEEisr-spiNED Stickleback, Sea-Addee, or Bismore, is wholly a marine species, 

 and is nearly as common as its companion on the picture on page 213. 



It is remarkably elongated in proportion to its width, and this fonnation, together with 

 its armature of sharp, tooth -like spines, has gained it the name of Sea- Adder. It is a voracious 

 creature, feeding on all sorts of marine animals, mollusks, worms, eggs, and fry, and minute 

 crustaceans. Mr. Yarrell advises the collector of marine crustaceans to examine carefully the 

 stomachs of the shore-frequenting fishes, and especially of this species, as he will be likely to 

 discover some curious species of those animals, too active or too small to lodge in his net, but 

 unable to avoid the quick eye and ready jaws of the Stickleback. The same writer mentions 

 that on one occasion, when a Fifteen-spined Stickleback had been caught with a net and 

 placed in water together with a small eel, three inches in length, the voracious creature seized 

 on the eel in a very short time, and contrived to swallow it. Tlie eel, however, was too long 

 to be wholly accommodated in the stomach of the Stickleback, and after a while was disgorged, 

 only partly digested. 



As in the case of the frog, the color of the Stickleback varies with singular rapidity, 

 being dull or bright according to the mental emotions of the individual. 



We now arrive at another family of fishes, in which the body is rather compressed — 

 i. e., flattened sideways — the eyes are large, and the mouth oblique. It is scientifically 

 known by the name of Berycidse, and all its members are inhabitants of the troi^ical and 

 temperate seas. 



Our fii'st example of this family is the Japanese Single-thorn. 



In all the fishes of this genus, the scales are rather large, very strong, and so closely com- 

 pacted together, that they form a strong, mailed covering to the body. The name of Mono- 

 centris, or Single-thoiTi, is derived from the curious modification of the ventral fins, which are 

 devoid of membrane, and are reduced to a single, very strong, and rather lengthened spine, 

 and a few very short rays. In the place of the dorsal fin are four or five thick spines, and the 

 shield-like scales of the body are rough, projecting, and keeled. 



The Japanese Single-thom is an inhabitant, as its name imports, of the seas of Japan, and 

 is almost, if not quite, the only species of its genus. It is chiefly remarkable for the size of 

 its head, the strong, thorn-like spines, and the mailed suit of hard and projecting scales. It 

 is of a tolerably iiniform color, its whole body being silvery-white, and its length is about six 

 or seven inches. 



The large-eyed and deep-bodied fish, Hoplostetiius, or Armed-breast, derives its name 

 from the strong and sharp spines which are placed on the scapular bone and the angle 

 of the pr;eoperculum. Like the last-mentioned species, it seems to be the only member of 



5enus. 



This fish is found in the Mediterranean, and is not uncommon on the coast of Madeira. 



