— 23 — LATER STAGES: PLEURONECTIDS 



areas W. S. and E. of the Dogger constitute his Flamborough Off and Eastern Outer Areas. 

 The triangular contour in the Flemish Bight encloses that part of his Southern Outer 

 Area from which the great majority of his samples were obtained in the spawning season of 

 ig07 (p. 159) and which also proved itself to be the spawning area par excellence of 

 the Southern North Sea. 



The black squares denote the positions where Wallace (''Report on the Size and 

 Age of Plaice at Maturity in the North Sea and English Channel", 2nd. Report, Pt. II. 

 North Sea Investigations, 1904— 5, pp. 56—58 Table I and Chart) found spawning 

 conditions most extensively indicated by his samples, (Nos. 9, 10, 11,26,27,28,31 and 32). 



The red circles denote the localities where Redeke and Van Breemen found pelagic 

 plaice eggs in quantity in January and February 1905 and 1906. ("Die Verbreitung der 

 planktonischen Eier u. Larven einiger Nutzfische in der Südlichen Nordsee" etc.: Ver- 

 handlingen uit hetRijksinstituutvoorhetOnderzoek der Zee. Tweede Deel, 

 1907—1908. 



The largest sized circles mark a catch of over 100 eggs per square metre of surface ; 

 the next size from u to 100 eggs and the smallest circles from l to lO eggs per square 

 metre. 



The small rings (not filled in with colour) denote positions where no plaice eggs 

 were taken. 



The black circles similarly denote positions at which the German Investigators 

 have taken plaice eggs in quantity in January, February and March (Symbols and Quan- 

 tities the same as above). See "Eier und Larven der im Winter Laichenden Fische der 

 Nordsee". II. Arbeiten der Deutschen wissenschl. Komm. f. die Internationale 

 Meeresforschung. (Helgoland) No. 12. 1909, Karte 1 u. 2. 



The small hollow rings denote positions where no plaice eggs were found. 



