Contributions to the biology of soine North 
Atlantic species of Eels. 
By 
Dr. Johs. Schmidt . 
(Witli Plate III.) 
In an article in “Nature”, 2158, 1911, I showed how the 
common European Conger-eel (C. vulgaris) reproduces both in the 
western and eastern part of the Mediterranean, mainly at or over 
great depths, the early fry being found in quantities in the surface- 
water far from the shores. As the Atlantic materiai collected by the 
“Thor” and by numerous other Danish vessels in earlier and more 
recent years has now been worked up, some further information can 
be given regarding the biology of this fish. From the same parts 
of the Atlantic we have three other Leptocephali, namely. Gonger 
( Gongromuræna ) mystcix, C. ( Congromuræna ) bctlearicus and Lep- 
tocephalus lanceolatus, and these may also be mentioned here. The 
common Conger, as is well known, is a fish of great economic im¬ 
portance, the second and third are of no value as food-fishes, whilst 
the adult of the fourth is as yet unknown; nevertheless, they are 
all of no little biological interest, and the same is the case witli 
two other forms, Leptocephalus ingoljianus and L. Andreae , which 
may be just mentioned here. 
The older full-grown larval stages and the transitional stages 
of the first three species have long been known, though from a few 
isolated localities only. After Giil, Delage and Gr assi and 
Calandruccio had shown that Leptocephali were the larvae of 
