20 O. NOKDGAARD (1915 



Pleuronectés flesus Lin. 



I have made some investigations into the ([uestion of nourish 

 ment at different stages with regard to this species (flounder; 

 Norw.: skrubflyndre), believing it to be a principal rival of the 

 plaice in this respect. 



Among a number of specimens from Orkla, 8 /5 1898, 11 were 

 rigth-sided, 1. 4 — 5.5 cm., and 1 left sided, 1. 3.8 cm. Contenls 

 of stomach consisted of insect larvæ. Specimens from Garten, 

 outside the mouth of the fjord, 20 /s 1903, 1. 3.5 — 3.8 cm., eon- 

 lained insect larvæ, ampiphoda and nematoda. Some larger 

 specimens tåken at same place and time, 1. 9.o — 12.4 cm., con- 

 tained isopoda and annelida. Among 61 young specimens from 

 Garten, 20 /s 1903, 40 right-sided, 1. 3.2—5.8 cm., and 11 left-sided, 

 1. 3.2 — 5 cm. In a haul made at the mouth of the Orkla, ]4 /o 

 1904, lengths varying from 4.5 — 6.3 cm., 6 were right-sided and 

 3 left sided. The ventricles contained amphipoda, schizopoda and 

 insect larvæ. 



On the 23 /7 1907, the mouth of the Gula, where there was 

 fresh water at the surface, we took, at a slight depth, a 2 cm. 

 long left-sided young speeimen of Pl. flesus, and on the 6 /7 1909, 

 at the inner end of Lofjorden, Aasen, abt. V2 m. depth, 5 right- 

 sided specimens 1. 2.2 — 3.5 cm. From the Borgenfjord, a field 

 of special interest in the hatching investigations. I have several 

 observalions to record. 27 /t 1909. Korsenleiret, abt. 0.5 m. sandy 

 bottom, 23 right-sided 1. 2.9 — 4.2 cm. and 10 left, 1. 2.7 — 4.i. 

 Stomach and inlestine contained insect larvæ and nematoda. 

 27 A 1909. Lønnemsleiret, abt. 0.5 m. 22 right-sided, 1. 3.7—5.5 

 cm. and 6 lefl, 1. 3.c — 5.4 cm. Similar observations from other 

 parts of Borgenfjord, as Vaasetleiret, Bolshavn, etc. 29 /7 1909. 

 Vaasetleiret, abt. 0.5 m. 25 right sided, 1. 3.7 — 5.2 cm. and 14 

 left, 1. 3.2 — 5.2 cm. Contents of stomach: insect larvæ, nema- 

 toda, isopoda and amphipoda. 



From the foregoing data il appears. inter alia, that the floun- 

 der in Borgenfjord exhibit a remarkable tendency to reverse. 

 In an eel seine haul, we may for instance find up to 50 °/o 

 reversed. Also in other parts of Trondhjemsfjord the percen 

 tåge of left-sided flounders may run very high. I had occasion 

 lo examine 91 flounders from hauls made in Buviken, (Sept. 

 and Oet. 1910), sizes ranging from 3.1 to 9.i cm., and found 50 

 right sided and 41 left. 



The somewhat larger stages of flounder also live on crusta- 

 ceans, worms and insect larvæ. In the ventricle of a speeimen 

 from Gulosen, ] % 1904, 1. 19 cm., were found remains of anne- 

 lida, and in specimens from Børsa, ir '/9 1904, 1. 10. 5 — 11. 3 cm. 



