4°4 
SPINY-FINNED GROUP 
are known as the three-spined (G. aculeatus), four-spined (G. spinulosus), and nine- 
spined sticklebacks {G. pungitius ); while in the United States G. novoeboracensis 
is the most familiar kind. The three-spined 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. Yery 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 
GROUP OF STICKLEBACKS. 
Sca-stickleback (upper figure); Nine-spined stickleback (middle figure); and Three-spined stickleback 
(lower figure), (nat. size). 
birth; so that we have here a second example of an annual vertebrate, the first 
being the one mentioned on p. 389. 
Sticklebacks are extremely pugnacious, and at the same time highly voracious 
fishes, the males engaging in fierce conflicts with one another; while both sexes 
consume a vast quantity of the fry of other fish, and are, therefore, most objec¬ 
tionable 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 Lincoln¬ 
shire farmer to rid a stream of sticklebacks, for a considerable time made four 
shillings a day by selling his catch at the rate of a halfpenny per bushel. In 
