86 THE SEAS 



they have been captured and marked. Their recapture 



on their way to the North Sea shows that they had travelled 



at the rate of about nine miles a day for some three months, 



but they were only a very short way on their total journey, 



for the next we know of them they must have arrived in 



the deep central part of the North Atlantic, known as the 



Sargasso Sea (a distance of some two to three thousand 



miles), although none of the spawning eels have themselves 



been seen there. There is, however, irrefutable evidence 



that they must have been to those regions, because at the 



end of winter and during spring the baby eels are there. 



The young eels are very unlike their parents ; in fact so 



unlike that the j&rst time one was seen it was considered to be 



a new species of fish and given the name of " Leptocephalus." 



They vary from a quarter of an inch to three inches in 



length according to their age. They are flattened sideways 



so as to resemble a leaf, and are quite transparent (Plate 35). 



These baby eels now start on the return journey and we can 



in this case get some idea of the rate they travel, for Prof. 



Schmidt has, by measuring very large numbers, shown that 



they take three years to reach the European shores once 



more. During the long journey across the Atlantic they 



grow, and it is by their giowth that their birthplace has 



been located ; catches made between our shores and the 



central Atlantic exhibit these eel larvae in ever decreasmg 



size (Fig. 13). Near the coasts they are about three 



inches long, but down in the locality of their birth they are 



only a quarter of an inch in length, and indeed, in this 



region, eggs have been taken that are without a doubt 



those of the parent eels themselves. The eggs are about the 



size of a pea, quite transparent, and drift in the water layers 



at depths of about a hundred fathoms, just like many of the 



other fishes' eggs mentioned earlier in this chapter. 



When the eel larvae have reached their destination on the 



