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Home Nature-Study Course. 



bottom may be able to answer in part at least. It may be necessary to cut 

 a hole through the ice, but if we dip with our net from the very bottom 

 of the pond, being careful to bring up some of the leaves and sediment, 

 we shall probably be rewarded by finding among the mass one or two 

 little fishes. They may be almost any of the little, fresh water fishes 

 such as chub, dace or minnows. Like many other fishes, they have buried 

 themselves in the mud and leaves to sleep through the winter. 



Having been fortunate enough to find a fish, let us take him home 

 and place him in a glass can or jar of water in order that we may see 

 how he is made. 



THE SHAPE OF THE BODY 



After watching a fish for a short time we cannot help being con- 

 vinced of his perfect adaptation to a life in the water. The boat-shaped 

 form, tapering gradually toward the head and tail, enables the fish to part 

 the water readily and swim with great rapidity. Fishes not having this 

 general form depend for protection on some other means of escape than 

 by fast swimming. 



THE FINS 



The normal fish has seven fins. The one on the middle line of the 

 back is the dorsal ; it may be divided into two or three parts. In that 



a, dorsal fin. b, caudal fin. c, anal fin. d, ventral fin. e, pectoral fin. f, gill- 

 cover, g, nostril. It, lateral line. 



case they are spoken of as first, second or third dorsal fins. The tail fin 

 is called the caudal fin. The fin on the lower middle line is the anal fin. 

 Like the dorsal fin it may be divided. Besides these unpaired fins are 

 two pairs of fins which correspond to the limbs of higher animals. The 

 first pair, or pectorals, are directly behind the gill openings. The second 

 pair are called ventrals, and are situated below and behind the pectorals. 

 Fins are made up of both soft and bony rods or rays connected by a 

 membrane. The soft rays are flexible and many jointed. The bony 

 rays are usually stifif spines and are never jointed. Not all fishes possess 

 spines. When they are present in a fin they precede the soft rays. The 



