322 PRICKLY FINNED THORACIC FISHES. 



but covered with a substance callous as a bone ; and 

 the fin attached to the gills has three spines. 



The cottus, or bull-head: the body of this fish is 

 formed like a wedge ; the head is flat, large, and fur- 

 nished with prickles and knobs ; and the fin which 

 covers the gills has six spines. 



The zens, or doree : the body oblong ; the head be- 

 vile ; the fin that covers the gills with seven rays ; and 

 from the upper jaw there is a loose floating skin which 

 drops into the mouth. 



The thrachipterus, or sabre; the body sword-like; 

 the head bevile ; a loose skin in both jaws ; and the fin 

 that covers the gills with six spines. 



The gasterosieus, or strickleback : the body broadest 

 towards the tail ; the head oblong ; and the fin that 

 covers the gills with three spines. • 



PRICKLY FINNED ABDOMINAL FISH. 



The silurus, or sheet-fish: the body oblong; the 

 head large ; and the fin covering the gills from four to 

 fourteen spines. 



The mugil, or mullet: the body oblong; the head 

 almost conical, with a furrow in the upper jaw where 

 the under one is received ; and the fin which covers the 

 gills with seven rays. 



The polynemus : the'body oblong; the head with a 

 beak ; and the fin which covers the gills with from five 

 to seven spines. 



The thentys: the body almost elliptical ; the head 

 abruptly shortened with a single row of strong and 

 even teeth ; and the fin covering the gills* with five 

 rays. 



The elops, or sea-serpent : the body slender ; the 

 head large ; the fin covering the gills double, with 

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