CHARACTERISTICS OF MARINE FISHES 151 



shape often said to be fusiform, that is, elongate, roundish to somewhat com- 

 pressed, and tapering toward the head and tail. A body with such a shape offers 

 a minimum amount of resistance in proportion to its size in swimming. Boat, air- 

 plane, and automobile designers have given careful study to the shape of the swift- 

 swimming fishes, especially mackerel, which are among the fastest and most 

 powerful swimmers and are the most perfectly "streamlined". All fusiform fishes, 

 however, are not swift swimmers, as, for example, codfish, weakfish, common 

 herring, shad, and many others. 



Eels, which are true fishes, popular opinion notwithstanding, have departed 

 rather widely from the "usual fish form"— the Atlantic herring— as they are 

 elongate, usually roundish, and snakelike. This shape makes it possible for 

 them to enter small crevices and penetrate dense vegetation. Some eels live 

 habitually in the crevices in coral formation where they await the approach of 

 small fish upon which they feed; others remain in muddy places or open water. 

 Nearly all eels have fair-sized mouths, provided with rather large teeth which 

 are useful in catching prey. At least some eels, as the writer himself has observed, 

 are capable of traveling, snake-fashion, short distances over land. 



Spadefish, doUarfish, butterfly fish, and angelfish differ from the "usual fish 

 form" in that they have short, deep, and strongly compressed bodies. In fact, some 

 of them are as deep as they are long. They all have small terminal mouths, most 

 of which contain brushlike teeth suitable for rasping plant growths from rocks, 

 piling, and other submerged objects. The writer has spent some time observing 

 spadefish foraging on algal growths among pier structures, and has seen them 

 feeding in narrow spaces that a broader or thicker fish could not have entered. 

 They apparently do not reject small animals that live among the plant growth. In 

 fact, this writer has enticed spadefish to take a small hook baited with bits of fish 

 flesh and particles of hermit crabs. These deep-bodied fishes are not "built" for 

 rapid swimming like the mackerel, but some of them are capable of making fair 

 headway. 



Skates and rays, too, are thin and flat, but in the opposite direction from that 

 of the compressed group discussed in the preceding paragraph. The typical ones 

 are strongly depressed, having very low and broad bodies. Although usually veiy 

 different in shape, they are related to the sharks. They also have cartilaginous 

 skeletons and possess several slits that lead to the gills. Because of their inferior 

 mouths and the shape of their bodies they are adapted to living on the bottom. 

 Many skates and rays have blunt teeth, arranged in series like the bricks in old 

 pavements. Such teeth are suitable for crushing hard-shelled animals, such as 

 oysters, clams, and other mollusks. Many of them have one to several large sharply 

 serrated spines, inserted on the upper surface at about the midsection of the 

 basal half of their slender, whiplike tafls. These spines are dangerous to man as 

 the animals are capable of inflicting serious wounds with them. There are poison 

 glands along the basal part of the spine that secrete a sort of venom. Although the 

 "sting" of these animals-sometimes called "stingerees"-is terribly painful, no 

 deaths definitely attributable to the venom seem to have been reported. 



Flatfish, that is, flounders and soles, are also strongly compressed. Oddly 

 enough they do not swim erect, except for a little while during their larval stages; 

 instead, they lie and swim on one side. Like the skates and rays, they dwell 

 chiefly on the bottom, and their underside, like the ventral parts of the skates and 



