754 



DEPTHS OF THE OCEAN 



represent stages prior to the fully grown leptocephalus, the five 

 lower figures representing stages of the " metamorphosis." 

 Without entering into the voluminous literature of the subject, 

 we may state that we found a certain regularity as regards the 

 geographical distribution of the various stages. Measuring the 

 forty-four specimens taken by the " Michael Sars," and arranging 

 them according to size (see Fig. 551), we see that they may be 

 divided into two groups, one ranging from 41 to 60 mm., and 



P'iG. 552.— Number of Larv./e of the Common Eel caught during the Expedition. 

 O full grown larvae ; + smaller larvae. 



the other exceeding 60 mm., in length. All the individuals of 

 the former group were taken south of the Azores as denoted 

 by crosses in Fig. 552, while all the specimens longer than 60 

 mm., i.e. the full-grown leptocephali, were taken north of the 

 Azores as denoted by circles. 



I presume that this peculiar distribution can only be ex- 

 plained by supposing that the eel spawns south of the Azores, 

 and that the eggs and larvae pass through their early stages 

 there, being later carried into the northern North Atlantic and 

 towards the coasts of northern Europe by the Gulf Stream. If 

 this be correct, the majority of the young eels found in Europe 



