444 THE EEL FAMILY. 



Mr Sandeman believes to be due to senility. Dr Glinther also, 

 in the article on 'Ichthyology' in the Encyclopaedia Britannica, 

 writes, 'So much only is known that they do not spawn in 

 fresh water, that many full-grown individuals, but not all, 

 descend the rivers during the winter months, and that some of 

 them at least must spawn in brackish water, or in deep water 

 in the sea ; for in the course of summer, young individuals from 

 3-5 inches long ascend the rivers in incredible numbers, over- 

 coming all obstacles, ascending vertical walls and floodgates, 

 entering every larger and swollen tributary, and making their 

 way over terra firma to waters shut off from all communication 

 with rivers.' 



The eels leave the rivers and enter the sea in autumn, but 

 according to Benecke, the migration begins in the upper 

 stretches of long rivers in April and May, and in the lower 

 reaches and shorter streams later in the season. Feddersen 

 says that the migration of the male eel to the sea happens 

 most usually earlier in the year than that of the female. 

 The time of migration in any locality seems to vary a little, 

 and to be dependent on the state of the river. The eel- 

 fishermen on the Eden notice that the migration takes place 

 on that river in the first heavy spate in October or November. 

 The main body of the eels comes down during the first night ; 

 by the third night they have all passed down to the sea. 



A comparison between the reproductive organs of the 

 migrating eel, and those of the eel at other seasons of the year, 

 would naturally be expected to afford conclusive proof that the 

 migration is for the purpose of spawning. This is only partially 

 the case. Although, in some instances, comparatively large ova 

 have been found in the migrating eels, still none which have 

 hitherto been examined have shown any considerable advance 

 in the development of the ovum. 



The important question, as to whether or not the eel takes 

 food during its migration, was solved by Jacoby, who examined 

 the stomachs of many hundreds of migrating eels. He in- 

 variably found the stomachs empty. He says that when the 

 eels commence to migrate to the sea they take no food, just as 

 other fish do during the spawning-period. 'The stomachs of 



