INTERESTING CITIZENS OF THE GULF STREAM 



81 



be divided rather sharply into the hunters 

 and the hunted. Mouse Fish and No- 

 meus, belonging to the latter class — the 

 one hides, the other lives under the pro- 

 tection of a powerful companion. 



WHEN THE FLYING-FISHES PLAY 



Flying-fishes, which are abundant, have 

 an even more interesting method of es- 

 caping their enemies, leaping above the 

 surface and. with favorable wind condi- 

 tions, shooting through the air for per- 

 haps as much as an eighth of a mile, sup- 

 ported by their long, stiff breast-fins, 

 widely spread at right angles to the body. 

 When there is a whole-sail breeze blow- 

 ing, they seem to fly also for sport. 



A flock of little flying-fishes no bigger 

 than herring, all in the air at once, gleam- 

 ing blue and white silver in the sun, is 

 one of the most beautiful sights of a 

 tropical sea. The very thought of it 

 takes one back to the broad blue expanse 

 of trade-wind ocean, warm decks lurch- 

 ing under foot, spray singing through the 

 shrouds, squawking tropic birds and bel- 

 lying square-sails which swing against a 

 background of fleecy cloud and sky. 



In spite of their agility, flying-fishes 

 form the chief food of the little schools 

 of Oceanic Bonitos, and of the Dolphins, 

 swiftest, most graceful, and most highly 

 colored of marine fishes, which prowl 

 over the high seas. 



THE PRIMEVAL SHARK IS STILL WITH US 



Ages before modern fishes, of which 

 we now find such countless variety in 

 tropical seas, had been evolved in the 

 slow process of evolution, there were 

 sharks which differed comparatively little 

 from those of the present day. Inter- 

 mediate forms have become antiquated 

 and dropped out, but the primeval shark 

 (Plate VI) is still with us. Especially 

 in the tropics they occur in great abun- 

 dance. 



Prowling singly along the edges of the 

 reefs, over the shallow flats, or through 

 offshore stretches of open water, they 

 hunt largely by sense of smell, and con- 

 gregate in numbers wherever food is 

 abundant. 



When a whale is being cut up at sea 

 it is astonishing how quickly the slender 



offshore Blue Sharks gather to the feast ; 

 it would almost seem from nowhere. 



By far the most abundant sharks nu- 

 merically are the ground sharks (Car- 

 charhinus). There is probably no trop- 

 ical or temperate coast-line where one or 

 more species of this genus do not enter 

 the bays and inshore water at the proper 

 season to give birth to their young. 



SHARKS PROPAGATE UNLIKE MOST OTHER 

 FISHES 



Though relics of a bygone age, as far 

 as bodily structure is concerned, sharks, 

 of all fishes, have the most highly devel- 

 oped reproductive system. Some lay a 

 few large eggs, each one protected by a 

 horny shell, but for the most part the egg 

 stage is passed through within the bodv 

 of the parent fish, and the young are born 

 well grown and able to fend for them- 

 selves. 



The Black-tip Shark (Carcharhiiuts 

 limbatus) is a small species of ground 

 shark, females of which are taken with 

 young in the Bay of Florida in April. 

 They are frequently hooked by tarpon 

 fishermen, who erroneously call them 

 "mackerel shark," and put up a spirited 

 fight when so hooked. They are usually 

 between five and five and a half feet in 

 length, and the young, about three to six 

 in number, are two feet long, or a little 

 less, when born. 



We have data concerning another 

 ground shark, Carcharhinus milberti, the 

 Brown Shark, which gives birth to its 

 young in Great South Bay. New York, in 

 midsummer. The mother sharks are a 

 little larger — six or seven feet — the 

 young, however, of about the same size. 

 but more of them, eight to eleven having 

 been recorded for this species. Some 

 kinds of sharks which grow much larger 

 have a proportionately larger number of 

 young. 



While evolution has been molding other 

 more modern fishes into a great variety 

 of forms to fit every niche in the infi- 

 nitely varied but unchanging environ- 

 ment of tropical seas, the shark has al- 

 ways been much as we find him today. 



A FISH THAT UTILIZES A SHARK AS A TAXI 



It is not surprising, therefore, that 

 there is a fish which owes its very re- 



