ON THE EARLY DEVELOPMENT 



OF THE "WEEVER FISHES 



(TRACHLNUS VIPERA AND TRACHINUS DRACO). 



Dr. J. BOEKE. 



1. Assist. for biology at the Gov Inst. for the Ex[)loration of the Sea. Helder, Holland. 



with Plate VII. 



[Uit het Rijks Instituut voor het onderzoek der zee.] 



Two species of Trachinus inhabit the North Sea, viz. the 

 Weever, Trachinus draco, and the lesser Weever, Trachinus 

 vipera. 



Both species are present in considerable abundance. The lesser 

 weever is captured more often on the English coast (in the 

 shrimpnets and sometimes in the trawl), Trachinus draco especially 

 on the Dutch coast, where they arrive in great numbers in summer 

 to spawn, though here too the lesser Weever is by no means rare. 

 Both decrease in numbers towards the north. In the » Deutsche 

 Bucht" Trachinus draco is caught sometimes in the bottom-nets *), 

 and is not rarely found in the neighbourhood of Helgoland at 

 the »Düne". Accordiug to Lührs (cited after Heincke) Trachinus 

 vipera too is found here. Professor Heincke himself did not fiud 

 any 2 ). In the Baltic according to Moebius and Heincke 3 ) only 



1) Fr. Heincke. Die Fische Helgolands. Wiss. Meeresunters. N. F. I Bd. 1896. S. 108. 



2) l.o. S. 108. 



3) K. Moebius und Fr. Heincke. Die Fische der Ostsee. 



