23.2 H err e: Philippine Eels 133 



When hatched the larva*, in common with those of some 

 other eels and most isospondylous fishes, are delicate, ribbon- 

 shaped creatures of glasslike transparency and with dispro- 

 portionately small heads. In this stage they are known as 

 Leptocephali, many having been originally described under this 

 name before their true relationship was recognized. 



Making their way to the surface, they drift toward the coast 

 of Europe or America, as the case may be, reaching the former 

 at the end of the second year, the latter at the end of the first. 

 Through the compacting of their tissues they become shorter, 

 lose their ribbon shape, and become eel-like, the European 

 species entering the mouths of rivers as small, unpigmented eels 

 about three years after their parents entered the sea. Here 

 they darken to the characteristic color and begin ascending the 

 rivers, the females going up to the headwaters, sometimes 3,200 

 kilometers or more from the sea. The males, so far as known 

 do not go beyond the brackish reaches of river mouths, and 

 mostly remain in salt-water lagoons and bays along the coast. 



The young eels sometimes ascend streams near the sea in 

 incredible numbers, so that it is, impossible to dip a bucket of 

 water without taking a large number. All ordinary obstacles 



are easily passed, and they reach lakes having an 

 915 meters above the sea. 



elevation of 

 Baird found hundreds 

 orwaTon^adToryoung^eTs crawling over the rocks and squirm- 

 ing in the whirlpools at the foot of Niagara Falls, which of 

 course they could not surmount. 



From specimens collected by the Siboga Expedition under 

 the direction of Dr. Max Weber, we may be certain that the 

 Indo-Pacific species of Anguilla have a similar life history 

 as many Leptocephali in different stages of development were 

 obtained, some of which Weber believes to belong to AngmUa^ 

 One of these, having a length of 115 millimeters, was collected 

 in the Sulu Sea at a depth of 1,270 meters. So far as I am 

 aware there are no data upon the breeding grounds of the 

 r* of Japan and the adjacent Asiatic coasts, or any of 

 the Indo-Pacific species. , 



Fmir «TwiPs of \nauilla are certainly known to occur in tne 

 PhSpinSthough their distribution is not determined .owing 

 to lack of material. At least two species occur in the , Mine 

 localities, and it is probable that all of them will be found to 

 occupy overlapping territory. 



