571 



Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar 1894. N:o 10. 



Stockholm. 



Observations on certain Flat-fishes. 

 By Dr. Einar Lönnberg. 



[Communicated 1894, December 12, by F. A. Smitt.] 



The Swedish Royal Board of Agriculture commissioned me 

 (June 1894) to make a study of the Scanian flounder-fishery in 

 the waters of the Sound and Cattegat. While discharging this 

 commission, 1 had the opportunity of making some observations 

 of flat-fishes, of which a report may perhaps not be out of place.. 



I will begin my report with some remarks about the cross- 

 species between the turbot (Bothus maximus) and the brill 

 (Bothus rhombus). These seem not to be so scarce as has been 

 hitherto supposed. During my fortnight's stay in Landscrona 

 and a fishing-trip I undertook to Anholt I made measurements 

 of rather över a hundred turbots and of nearly the same number 

 of brills and observed about as many more of each species, let 

 US say, about four hundred in all. But among these 1 found 

 as many as five specimens which certainly were hybrids. That 

 makes more than one per cent of hybrids among the total 

 number of parent forms. All the hybrids and all the brills 

 were caught in the Cattegat near the Island of x\nholt and the 

 same was the case with very few exceptions with the specimens 

 of turbot which were caught in the Sound. 



That cross-species exist between two forms so closely related 

 as the turbot and the brill does not seem very stränge, especi- 

 ally as they spawn about the same ti me of the year and at the 

 same place. 



1 found most brills in the neighbourhood of Anholt had 

 done spawning by the early part of June; many turbots too 

 were in the same state and the remainder had flowing roe. 



