THE FRESH WATERS 165 



at the other side of the room, apparently 

 dead; however, when returned to the water 

 they swam about apparently none the worse 

 for their excursion." Once settled down in 

 suitable quarters the elvers begin to feed and 

 to grow, and are now known as "yellow eels." 

 Their food consists at first of worms, larvae, 

 and small fishes, but as they grow they become 

 very voracious, and will attack water voles 

 and water-fowl, and even larger fishes, among 

 which they do serious damage. There is even 

 a case on record of an eel, 5 feet long, which 

 attacked a swan! The owner saw the swan 

 struggling violently, with its head under 

 water. He went to its assistance and found 

 that its head had been seized by a large eel, 

 which held on so obstinately that it allowed 

 itself to be caught and landed. 



About the third summer of an eel's life in 

 fresh water its scales begin to grow. It is an 

 interesting fact that naturalists can tell the 

 age of an eel, or at least the length of time it 

 has spent in fresh water, by examining its 

 scales under the microscope. Each scale is 

 arranged in little zones or rings studded with 

 tiny, limy knobs, separated by narrow rings 

 of smooth material. "This structure is due 



