HARD-CHEEKED ACANTHOPTERYGII. SQUAMIPENNES. 31 



bottom of the water. The swimming-bladder is usually large, 

 and furnished with powerful muscles for its compression. To 

 this group also belongs the genus Cottus, or Bull-head, which 

 has a large and horizontally-flattened head, eyes looking upwards, 

 and its skin almost destitute of scales, and of a dusky hue : it 

 lurks among stones in the beds of rivulets ; and its food consists 

 of aquatic insects or small worms. The Scorpcena, or Hog-fish, 

 has the head flattened sideways, and armed with spines ; it is 

 a marine fish, associating in shoals, and haunting the rocky 

 shores. Allied to this is the Sebastes, or Norway Haddock, which 

 inhabits the northern seas, and is an important article of food ; 

 the Greenlanders use its long spines as needles. Also belonging 

 to this group is the Gasterosteus, or Stickleback, of which there 

 are several species, some inhabiting salt water, and others fresh. 

 The body has no proper scales, but is more or less plated at the 

 sides ; and the abdomen is covered by a sort of cuirass, formed 

 by a union of the pelvic and humeral bones. The common name 

 of these fish is derived from the circumstance, that instead of 

 possessing two dorsal fins, it has only one, the anterior being 

 replaced by a set of sharp spines varying in number ; whilst the 

 ventral fin is in the form of a sharp spine without any rays. 

 These fishes are active and rapacious, attacking other fishes with 

 great ferocity, and devouring almost any small animal that 

 comes within their reach. The Fifteen-spined Stickleback has 

 been seen to undergo remarkable changes in its hue, under the 

 influence of terror. 



557. We may pass over the SCI^NID^:, or Maigres, and the 

 SPARID^E, or Sea-Breams, to notice the SQUAMIPENNES, or Scaly- 

 finned fishes ; which are thus designated, from the soft, and even 

 the spiny, portion of the dorsal fins being so covered with scales, 

 as not to be easily distinguished from the rest of their bodies. 

 The body, too, is usually itself much compressed, or flattened 

 laterally. The Chcetodons, which constitute the types of this 

 family, are beautifully-coloured fishes of singular figure, abound- 

 ing in the seas of the hotter climates. Their most common tints 

 are black and yellow ; but metallic blues and greens are not 

 unfrequent. Sometimes the colours are disposed in spots ; but 



