OPPIAN 



* earth's entrails ' (yTys evrepa, earth-worms), which 

 grow spontaneously in mud and moist ground. Eels 

 have in fact sometimes been seen to emerge from 

 such earth-worms and at other times have been 

 rendered visible when the earth-worms were laid 

 open by scraping or cutting. Such earth-worms are 

 found both in the sea and in rivers, particularly where 

 there is decayed matter." Cf. 517 b 8, 567 a 21, 

 569 a 6, 608 a 5. 



Till within the last half-century or so the problem 

 remained in much the same position as it was in the 

 time of Aristotle, but in recent years and in particular 

 through the systematic and elaborate investigations 

 of Dr. J. Schmidt, the life-history of the Eel has been 

 greatly elucidated. The result of these investigations 

 may be briefly summarized : 



The Eel is oviparous and its spawning-ground is 

 in the deep waters of the Atlantic Ocean near the 

 Bermudas. Thence the larval " Ribbon-eels " travel 

 eastward, a direction of migration which is instinctive 

 and not due to drift of the current, as is proved by 

 experiments with bottles and the like cast overboard. 

 After a journey which lasts for about two years the 

 young Eels in their third year, when about three 

 inches in length, enter the European rivers, being 

 now known as Elvers or " Glass-Eels." They ascend 

 the rivers in spring, travelling in compact bodies and 

 swimming close to the river-banks. They show re- 

 markable determination in their upward journey, 

 overcoming such obstacles as waterfalls by wTiggling 

 through the grass upon the banks. Examination of 

 the growth-rings on the minute scales, on the otoliths 

 (" eaT-stones "), and on the centra of the vertebrae, 

 shows that at three years of age, after a year in fresh 



Ixxii 



