308 NATURAL HISTORY. 



The Bony Fishes. 



First among the bony fishes, — the group which contains all of onr 

 most familiar forms, which have the skeleton, not cartilaginous, but com- 

 posed of hardened bones, — come the eels, familiar to all. These are long, 

 cylindrical fishes, occurring in both salt and fresh water. They are car- 

 nivorous, eating almost everything of a size suitable to be swallowed ; and 

 when living prey is not handy, they play the part of scavengers, as all 

 readers of the ' Ingoldsby Legends ' will readily recall. 



Until a very recent date the whole life-history of the eel was involved 

 in mystery, and even now there are many undecided points. Still, the 

 following account is probably correct, so far as it goes. The same species 

 of eels are found in both salt and fresh water. In the spring immense 

 numbers of small individuals make their way up the rivers and streams. 

 When they start on these migrations, they are little beauties, an inch 

 and a half or two inches in length, and so transparent that every feature 

 of their internal anatomy can be seen and studied through the body 

 walls. One can see the heart beat, and the blood stream through the 

 gills and blood-vessels : they seem as if made of glass. Arrived at their 

 destination, they rapidly wax and grow fat. They prowl about, mostly 

 at night, burrowing in the mud in search of worms and cray-fish, or lurk 

 behind some stone, to pounce upon some unlucky fish which may venture 

 too near. 



At last, after several years, they become adult, and again are seized 

 with a migratory impulse, but this time their course is towards the sea. 

 In the autumn they set out, traveling mostly by night on their long 

 journey, sometimes hundreds of miles, to the salt water ; for in the ocean 

 alone will they reproduce. The fishermen tell, with every appearance of 

 truth, of the immense numbers of eels which conores-ate in the shallow 

 bays in the months of October and November. They coil themselves in 

 large masses, sometimes several feet in diameter ; and the existence of 

 these masses seems to be in some w T ay communicated to all the others 

 within a considerable distance ; for as soon as a bunch begins to be formed, 

 they come from every direction. The fishermen take advantage of these 

 congregations ; stationing themselves near one, they spear the eels as they 

 come swimming towards the spot ; but they carefully refrain from disturb- 

 ing the bunch, since the minute it is alarmed the individuals scatter 

 instantly in every direction. It would appear that this bunching is con- 

 nected with the laying of the eggs, but on this point nothing certain is 

 known. 



We have said that the eels will not reproduce in fresh water ; the evi- 



