158 ACANTHOPTERYGII. MAILED CHEEKS. 



Seven species are now supposed to occur in Bri- 

 tain, though Naturalists are not quite agreed as to 

 those which possess well-defined specific characters, 

 and those which constitute mere varieties. Belon 

 first described the Three-spined Stickleback, and 

 Cuvier and Valenciennes have pointed out that 

 three species have been confounded under the name 

 Aculeatus, the name indifferently applied by authors 

 to them all. Hence the difficulty of accurately 

 appropriating the observations made by the older 

 writers without the necessary discrimination. This, 

 however, is a matter of no great moment. Some of 

 these little fish closely correspond, not only in their 

 external appearance, but also, in all probability, in 

 their habits and dispositions, which are sufficiently 

 striking. They bear a conspicuous part in almost 

 all the Faunas of Europe, and are not confined to 

 the Old World, having many representatives in 

 North America, not excluding Greenland. Nor are 

 they restricted to fresh water, abounding also in the 

 sea, as has been especially remarked in the Baltic. 

 We have in former pages introduced them to notice 

 in connexion with the phenomena of the varying 

 colours of fishes, (see pp. 80, 85) ; they spawn in 

 different seasons of the year. They are strongly 

 armed against the attacks of other fish, and are very 

 pugnacious themselves. They are also tenacious of 

 life, and can subsist for a considerable time out of 

 the water, if lodged amongst moist herbage. Bloch 

 states they live only for three years, an assertion 

 wdiich requires confirmation. They are very active 



