52 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



increases in size, the eye becomes relatively smaller, and the slender 

 spike-like teeth are lost. These changes are completed by autumn. 

 Some doubt exists with regard to the particular water level which 

 these creatures normally inhabit, but it seems most likely that they 

 usually remain somewhat below the surface, probably rising at night 

 and sinking lower down in the daytime. 



A remarkable feature of the later stages is the reduction in the size 

 of the larva. Instead of growing larger as it becomes older, it grows 

 smaller and smaller, so that an individual which had been over three 

 inches long may shrink to the length of about two inches, and the 

 ribbon-like form may dwindle into a thread-shaped body. This 

 phenomenon of the reduction of the size of a larva while undergoing 

 metamorphosis has been observed in the case of certain other ani- 

 mals, and is probably due to the fact that the larva, during this 

 gradual transformation, which, in the case of the eel, according to 

 Schmidt, requires about a year for completion, does not take any 

 nourishment. All the observers, Grassi and Calandruccio, as well 

 as the Danish investigators, agree regarding this abstinence from 

 food. A, C. Johnson "investigated over thirty specimens from the 

 North Sea and the Danish waters and found the alimentary canal 

 empty in all of them." 



Later in the autumn and winter the larvae approach the shores, 

 meanwhile gradually assuming the true eel-like form. The time of 

 their entrance into the mouths of the rivers depends partly upon the 

 distance of those mouths from the 500-f athom line, and to some extent, 

 probably, upon the temperature of the water. In France, England, 

 and Ireland, they may begin to enter the streams as early as January 

 and Feburary; in Denmark and Norway, in March, and chiefly in 

 April. In this country the exact time of their arrival -has not been 

 accurately noted; but the writer has seen them in Rhode Island 

 streams, particularly in the Taunton and Warren rivers, in the latter 

 part of April and early May. 



During the entire period of its larval history the young eel remains 

 almost perfectly transparent. As Gill says, "the body is so diapha- 



