MARINE VERTEBRATES 337 



Our littoral species include two well-known fishes (the Greater 

 and Lesser Weavers) that are dreaded by fishermen on account of 

 the very painful wounds they are capable of inflicting, and the 

 smaller of the two is also a considerable annoyance to bathers on 

 certain sandy coasts. 



The Greater Weaver (TracJiinus draco) lives at the bottom of 

 deep water, and is often dredged up in the trawl. Some fisher- 

 men call it the Sting Bull, and always take the precaution of cut- 

 ting off the poisonous spines before disposing of the fish. It lives 

 on the bottom with its mouth and eyes directed upward, always in 

 readiness to seize its unwary prey, and the sharp spines of the 

 dorsal fins are kept erect for the purpose of promptly attacking 

 approaching foes. Its mouth and palate are armed with sharp 

 teeth which render the escape of its prey almost impossible. The 

 smaller species ( T. vipera) seldom exceeds six inches in length. It 

 lives in shallow water on sandy coasts, with dorsal spines erect ; 



FIG. 243. THE LESSER WEAVER 



and the wounds it produces on the unprotected feet of bathers are 

 often exceedingly painful on account of the injected poison, which 

 also causes the part to swell and turn to a dark purple colour. 



The remaining important families, although they contain well- 

 known British food-fishes, do not include littoral species, and for 

 this reason we shall pass them over with but brief notice. 



The Mackerel (Scomber vernalis) belongs to the family Scom- 

 beridce, and is so well known that no description need be given for 

 the purposes of identification. We have already referred to it as a 

 beautiful illustration of protective colouring, its upper surface 

 resembling the ripples of a deep green sea and the lower the 

 brightness of the sky. Mackerel swim in shoals in the open sea, 

 pursuing and devouring the fry of herrings and other fish ; and in 

 order that they may be enabled to cover enormous distances their 

 muscles are richly supplied with blood. This not only gives a 

 pinkish colour to the flesh, but results in a greater amount of 



z 



