156 



normal positiou and swim about actively when disturbed. At rest 

 they hang with the front end inclined downwards, as is also the 

 habit in other very young fishes under these conditions. The oil- 

 globule has now taken a position at the foremost part of the 

 yolk-sac. The larvae are still perfectly translucent, and but for 

 the strongly marked black spots are difficult to see. A larva just 

 hatched with the rnouth and the vent still closed is figured in fig. 6, 

 one two days old with the breast-fins already developed in fig. 7. 

 At about four or five days after hatching the yolk has almost 

 entirely disappeared and the larvae die. Until this period they 

 remain entirely translucent but for the black pigment spots. The 

 eyes too are now quite black. A larva, in which both the yolk- 

 sac and the oil-globule are reduced to very small dimensions, 

 (five days after hatching) is figured in fig. 8. 



During this development the eggs and larvae present some 

 prominent diagnostic features, that enable us to distinguish them 

 pretty certainly from all the other pelagic eggs found at the 

 sanie time in the North sea. 



Judged by their size and by the presence of an oil-globule only 

 they may in the earliest stages of development be confounded 

 with the eggs of scomber scomber, with the smallest eggs of trigla 

 spec, with the eggs of rhombus maximus, of mugil capito, of lota 

 molva, of caranx trachurus, or with very large eggs of motella 

 mustela. Now the eggs of lota molva have a much larger oil- 

 globule (about 0,30 niM.), the yolk of the eggs of caranx tra- 

 churus is segmented, the oil-globule of the egg of scomber scomber 

 is larger and has according to Holt l ) a cloudy appearance, and 

 these eggs may therefore in many cases be distinguished from the 

 eggs of the weever. But even where these characters are not sufficiënt 

 to distinguish the several species from each other, the strongly 

 marked punctuation and the wrinkled appearance of the egg- 

 capsule may be of use to separate the eggs of Trachinus from 



1) Heincke and Ehrenbaum found it in all cases entirely uncoloured. 



