274 CHARACTERS OF VERTEBRATE ANIMALS 



From behind each of the sharp spines of the large first dorsal 

 fin projects a long filament. A small part of the upper side 

 is dark -brown, which shades into golden -yellow farther down, 

 and again into brownish white. On each side of the body there 

 is a large round blotch, dark in colour with a lighter margin. 

 By the ancient Romans it was regarded as sacred to Neptune. 



5. Mackerel Family. - - This is an important group of car- 

 nivorous food-fishes, abundant in the temperate and tropical seas 

 of both hemispheres. They are remarkable for their powers of 

 swimming. The Common Mackerel (Scomber scomber) suggests 

 the lines of a racing-boat in the beautifully graduated curves of 

 its rather slender body, terminated behind by a well-developed 

 caudal fin shaped like the head of a broad arrow. Rows of 

 pointed finlets fringe the body in the spaces between the tail 

 and the anal and second dorsal fins. 



Another member of the family, sometimes taken off the 

 south of England, and the object of an important Mediterranean 

 fishery, is the Tunny (Thynnus thynnus], which may attain the 

 length of 10 feet and a weight of more than 1000 pounds. 

 Smaller species of the same genus are the Bonito (Thynnus 

 pelamys] and Albicore (Thynnus albicora), which prey largely on 

 Flying- Fishes, and, being rendered conspicuous by this habit, are 

 often mentioned in accounts of voyages. 



6. Angler- Fish Family. This embraces widely-distributed 

 fishes of extraordinary form, some of which frequent shallow 

 water, while others drift with sea-weed in the open ocean, and 

 still others live at great depths. A well-known British species 

 is the Fishing- Frog {Lophius piscatorius), with its body dwarfed 

 by an enormous head, the wide gaping mouth of which, armed 

 with numerous teeth, is a regular death-trap for unwary little 

 fishes of all sorts. The first dorsal is reduced to its long spines, 

 the foremost of which terminates in a soft flap. The upper side 

 is of a blackish brown and the under side white. 



7. Bull-Head Family. - - These are small ground fishes of 

 wide distribution, and mostly found near to land, while there 

 are also fresh-water forms. A common British species is the 

 Bull-head or Miller's Thumb (Coitus gobio\ common in brooks, 

 as every school-boy knows; while just as common along our 

 shores is the Sea-Scorpion (Coitus scorpius], which has much the 

 same appearance. 



