94 



A HISTORY OF FISHES 



tures. In the Scad or Horse Mackerel (Trachurus), a member 

 of a large tribe of fishes known as Pampanos or Carangids 

 (Caringidae), the lateral line is armed with a row of numerous 

 keeled, bony shields, which in the tail region arc armed with 

 sharp, knife-like spines (Fig. 41B). Somewhat similar spinous 

 structures in this region occur in many of the Gurnards ( Trigla) . 

 The members of a family of Cat-fishes found in the rivers of 

 South America [Doradidae) possess a row of strong, bony scutes 



Fig. 41. — FISHES WITH SCUTES. 



A. Sturgeon (Acipenser sturio),x\ ; b. Pampano or Carangid (Caranx chrysos), 

 xi; c. Unicorn-fish (Naseus brevirostris),X^ \ d. South American Cat-fish 

 (Megalodoras irzvini), X | ; e. Three-spined Stickleback (Gasterosteus aculeatus), 



xi. 



along the middle of either side, each of which is armed with a 

 sharp spine and bears a superficial resemblance to the bucklers 

 of the Sturgeons (Fig. 41D). 



In the little "Tiddler" or Three-spined Stickleback {Gastero- 

 steus) scales are wanting, but there is a series of large plates 

 along each side, which in some specimens extends from the 

 head to the tail, but in others is reduced to two or three plates 

 behind the gill-opening (Figs. 28f; 41E). The Stickleback is 

 equally at home in salt or in fresh water, and there seems to be 

 some definite connection between the salinity of the water and 



