80 ACANTHOPTERYGII. — TRIGLAD^. 



serve them as organs of touch, endowed with a 

 sensibility to impressions that are indispensable 

 in the situations where they haunt, as bottom 

 feeders. 



About two hundred and sixty species are enu- 

 merated in the Family, of which just one tenth 

 part are European. 



To this Family belongs a genus of fishes con- 

 taining many well-known inhabitants of our 

 coasts and rivers, the Sticklebacks {Gasterosfeus). 

 We have seven species, all of them of small size, 

 some of which are familiar to every truant school- 

 boy by their abundance, their pigmy dimensions, 

 their armature of spines and plates, their vivacity 

 and boldness, and the beautiful tints of green, 

 crimson, and silver, with which they are frequently 

 adorned. 



These little fishes, however, present other 

 claims to our attention ; for they afford additional 

 examples of an instinct which has been considered 

 almost if not quite unknown in the Class to 

 which they belong, that of nest-building. The 

 habits of one of these species, which appears to 

 be the commonest of the Three-spined Stickle- 

 backs {G. trachurus) have been described by a 

 careful observer in a little-known periodical, 

 called " The Youth's Instructor;" and his account 

 carries its own guarantee of correctness with it. 

 " In a large dock for shipping on the Thames," 

 observes this writer, " thousands of these fish 

 were bred some years ago ; and I have often 

 amused myself for hours by observing them. 

 While multitudes have been enjoying themselves 

 near the shore in the warm sunshine, others have 

 been busily engaged in making their nests, if a 



