132 THE STORY OF FISH LIFE. 



these remarkable and puzzling fish were larval eels 

 — not only of fresh water, but marine forms also. 

 These larvae, furthermore, brought to light some 

 very extraordinary facts, one of the most impor- 

 tant of which concerns the law of growth. Thus 

 they go on increasing in size and favour daily, up 

 to a certain point, when they actually begin to 

 grow backwards, that is to say, they decrease in 



size from daj 



to day up to a 

 certain point, 

 then growth 

 recommences; 

 with this new 

 growth they 

 assume the 



Fig. 12.-Fish Ti-ansfomations. A. B. C. Three ^v.Qraptpricjf 1 p 



^tagesia the life history of the Eel: showing t/lldidCLtJiift) t lo 



the gradual decrease in size as the fish grows round Cel-like 



older. With the decrease in size the eel-like - ' , 



shape is gradually acquired. At C. the mini- lOrm, aSCeilQ 



mum decrease has been reached. The young i. ^ tVip Qiir 



fi>h has now reached the " Elver" stage and ^^ oui- 



asL-ends rivers to complete its growth into the f ac e O f the 



"•^•^"^"^* sea, and in 



the case of the fresh- water species, make their 

 way with all speed up the rivers, in which 

 journey we shall follow them in the next 

 chapter (p. 144). The accompanying figures give 

 an indication of the delicacy and transparency 

 of these fish at this early stage, the internal 

 structures in the living larva being quite dis- 

 tinct (fig. 12). The curious changes in the rate 

 of growth and the small size of the head, very 

 striking features of the larvae at this stage, are 

 also well brought out in the figures. When a 

 Leptocephalas has completed the first stage of 



