438 THE EEL FAMILY. 



described by many authors. Parnell, in this connection, says, 

 'In June the young are seen, from 2 3 inches in length, 

 making their way up the fresh-water rivers in innumerable 

 multitudes, keeping a few inches below the surface, and at a 

 short distance from the bank. No obstacle appears to arrest 

 their progress. They have been known to climb up posts, and 

 to ascend into trees. They have also been observed crawling 

 over land from one pond to another.' That eels very often 

 travel over wet grass from one piece of water to another is a 

 well-known fact. The presence of eels in ponds, into which 

 they have not been introduced, and which are isolated from all 

 other waters, can only be accounted for by the passage of the 

 eels over land from a stream connected with the sea. Some 

 persons have asserted that eels crawl over fields in search of 

 slugs, etc. ' The adult eel,' says Jourdain, ' will travel over wet 

 grass to ponds or water-courses which have no direct communi- 

 cation with the sea. Out of water, the eel swallows air into its 

 branchial chamber, the straight opercular opening of which 

 closes very exactly. The gill is then in a humid chamber, 

 where the air gives up a portion of its oxygen to the branchial 

 lamellaB, which can be partly separated from one another by the 

 play of the muscles of the respiratory apparatus. This is one 

 of the conditions which favour the long survival of the fish out 

 of the water.' 



The question as to whether or not the male eel enters fresh 

 water has given rise to much difference of opinion. It was 

 generally believed that the male eel never left the brackish or 

 salt water near the coast, except at the period of reproduction, 

 when it joined the females which had migrated from the fresh 

 water streams. This view has now been modified. The ob- 

 servations of Hermes, Pauly and Feddersen have proved that 

 males do go up the rivers into fresh water. 



Such then are the general characters of the immigrations of 

 the young eels into fresh water. 



As regards the sexual organs we have already noticed that 

 the female organ or ovary (roe) only commences to make its 

 appearance after a length of seven inches is attained. The 

 ovary of the eel was first described by Mondini in 1777, and 



