2774 THE BONY FISHES AND GANOIDS 



STICKLEBACKS, FLUTEMOUTHS, AND TRUMPET FISH Families GASTRO- 



STEIDsE, AULOSTOMATIDsE, and CENTRISCID^ 



Although the third of the above-named families is regarded by Dr. Giinther as 

 forming a group apart, we may follow Day in placing the whole three in a single 

 section, characterized by the spinous dorsal fin, when present, being either short or 

 formed of isolated spines, and by the generally abdominal position of the pelvic 

 fins, which in some instances are imperfectly developed. 



Familiar to every home-born Englishman as the fish upon which, in 

 common with minnows, he made his first experiment in angling with 

 the aid of a bit of twine, a bent pin, and a worm, the sticklebacks have the honor 

 not only of representing a geuus ( Gastrosteus) , but likewise a family by themselves. 

 Taking their name from the presence of a variable number of isolated spines in ad- 

 vance of the soft dorsal fin, sticklebacks have the body more or less elongated and 

 compressed, the cleft of the mouth oblique, and the teeth villiform. The gill cover 

 is unarmed, and the cheek covered by the infraorbital bone; and in place of scales 

 there are generally large plates along the sides of the body. The pelvic fins, although 

 abdominal in position, are connected with the pectoral girdle by means of the pelvic 

 bones, and consist of but one spine and a single ray; and there are but three bran- 

 chiostegal rays. Confined to the Temperate and Arctic zones of the Northern Hem- 

 isphere, where they are represented by some half-score species of small bodily size, 

 sticklebacks are mainly fresh-water fishes, although the sea stickleback (G. spin- 

 achia) is a marine or brackish -water form, and all the rest can live as well in salt as 

 in fresh water. The British fresh-water representatives of the genus are distin- 

 guished by the number of the dorsal spines, and are known as the three-spined (G. 

 aculeatus), four-spined (G. spinulosus), and nine-spined sticklebacks ( G. pungitius) ; 

 while in the United States G. novceboracensis is the most familiar kind. The three- 

 spiued stickleback is a singularly variable species, the plates which are present on 

 the sides of the body in some specimens, being wanting in others; the unprotected 

 condition being especially common in the race from Central Europe. Very different 

 in appearance from the others is the fifteen-spined, or sea stickleback, in which the 

 body is very long and thin; this species ranging as far north as Norway and the 

 Baltic. It has recently been ascertained that all the individuals of this stickleback 

 die within a year of their birth; so that we have here a second example of an annual 

 vertebrate, the first being the one mentioned on p. 2759. 



Sticklebacks are extremely pugnacious, and at the same time highly voracious 

 fishes, the males engaging in fierce conflicts with one another; while both sexes con- 

 sume a vast quantity of the fry of other fish, and are, therefore, most objectionable 

 denizens of preserved waters. It is not indeed that a single stickleback can do a 

 very great deal of harm, but the mischief results from the enormous numbers of 

 these little marauders. As an instance of this, we may once more quote the well- 

 known statement of Pennant, that a man employed by a Linconshire farmer to rid 

 a stream of sticklebacks, for a considerable time made a dollar a day by selling 

 his catch at the rate of a penny a bushel. In fighting, the males make full use 



