14 



FISHES 



. THE FISH'S PLACE IN NATURE. 



DAVID STARR JORDAN. 



SOME animals have their hard parts 

 on the outside. These may be a horny 

 coat or skin, such as the beetle has, or a 

 double shell, like the oyster's, or a single 

 shell, like the house of a snail. Or they 

 may be a hard crust, like the lobster's 

 coat of mail, or a brittle crust, like the 

 sea-urchin's, or with tough nodules on a 

 leathery hide, as in the star-fish, or any 

 one of a hundred variations from these. 

 But in all such cases there is no back- 

 bone, no true skeleton and no real skull. 



Then there are a host of animals that 

 have their hard parts on the inside. When 

 this is the case the animal has a regular 

 head, generally with a skull inside to pro- 

 tect a brain from hard knocks. 



Then behind the skull is a backbone 

 made up of a number of separate joints of 

 bone. To the skeleton other bones are 

 attached to help the animal to move him- 

 self about on land or in the water. Some- 

 times these bones grow out as legs, with 

 toes and claws at the tip of them. Some- 

 times they take the form of wings or they 

 may spread out into flat paddles or oars 

 of one kind or another, and these we call 

 fins. What shape the parts take depends 

 on what the animal does with them, for 

 every kind of beast is built with direct 

 reference to his business in life. 



The backboned animals are the highest 

 of all the animal kingdom. That is. in 

 general ; they can do more things, they 

 iiave a greater variety of relations to the 

 things around them, and they are more 

 definitely fitted for a high position. Some 

 ■of them are not very high nor very intel- 

 ligent, even as compared with their lower 

 brethren, the insects. The ant is a tiny 

 creature, with no skull and no backbone, 

 and cannot do any very big thing. But 

 .<;he is a verv wise beast by the side of a 



carp or a herring. Still, on the whole, 

 the backboned animals are the highest 

 and as you and I both belong to that class 

 we could never afford to confess to any 

 doubts as to their superiority. 



But we are the highest of the type — 

 that is, we men — and the rest of the tribe 

 are all lower. And the lowest of all back- 

 boned animals we call fishes. And we 

 shall know a fish when we see one be- 

 cause the hard parts or skeleton are on 

 the inside, and he stays in the water, 

 breathing the air which is dissolved in it. 

 and he has never any toes or claws or 

 feathers. He breathes with gills and he 

 swims with fins. He has no hair or feath- 

 ers on his body and when he has any 

 cover on his skin at all it takes the shape 

 of scales. A fish is a water backboned 

 animal. A backboned animal is called a 

 vertebrate. A fish is therefore a water- 

 vertebrate. 



There were fishes before there were 

 any other kind of vertebrates. They have 

 been on the earth longer than birds or 

 beasts or reptiles. They came first, and 

 we have good reason to believe that the 

 fishes are the ancestors of all the others. 



But when the forefathers of the land 

 animals found means of keeping alive on 

 the land, so many new opportunities 

 opened out to them and they found so 

 much variety in their surroundings, that 

 they throve and spread amazingly. And 

 there came to be many kinds of them, 

 of many forms, while the rest of the tribe 

 kept in the water and stayed fishes. 



And there was always a host of these, 

 and nearly all of them had fishes for their 

 food. So" they fought for food and 

 fought for place. Those who could swim 

 fastest got away from the rest, and those 

 who could move quickest got the most to 



