28 r. T. CLEVE. THE PLANKTON OK TIIE NORTH SEA ANO THE SKAGEKAK. 



Ceratauliiia Bergouii H. Per. — April: 57° N. 6° E. r. July to October: M. r, V. 

 -|- r. Noveniher: sparingly from the coast of Holland to Sk.; Viiiga (30 m.) r; M. and 

 V. r. December: M. r, V. er. 



Chaetoceros atlauticus Cl. — Fehriiary: 58° N. 3° E.; 56° N. 4° E.; Skagen, every- 

 where rare. April: 58° N. 10° E. r. Noveniher: E. of Scotland rr. 



C. borealis Brtw. — Janiiary: the central North Sea c, aloiig the west-coast of 

 Sweden, irom Vinga to Väderö r. February: r at 57° N. 7° E. and 58° N. 3° E.; M. rr. 

 March: from 56° 33' N. 12°26'E. to Måseskär not rare. April: E. of Scotland r; area 

 between 55° N. 6° E., 57° N. 5° E. and Sk. (common along the Danish coast); Skagerak c 

 to r; M. and V. -\-. May: M. and V. not rare. June: the Shetlands r; M. and V. r. 

 October: M. and V. r -\-. November: N. of Jutland, common to rare; Vinga not rare; 

 M. very common; V. c. December: M. -\-, V. c. 



Var. Briglitwellii Cl. — January: the central Skagerak r, Vinga -|-, M. and V. ;•. 

 February: M. rr. March: from 56° 33' N. 12°16'E. to M. r. April: Sk. and M. not 

 common. May: M. not rare. October: V. rr. November: Sk. r; M. and V. r. Decem- 

 ber: V. +. 



C. bottnicus Cl. — March: Vinga r. 



C. brevis Schutt. (C hiemalis Cl.) — February: M. -|-, V. c. March: from 56° 

 33' N. 12°16'E. to M. r. April: 56°— 57°N. 4°— 5° E. r; Sk. r. June: V. r. October: 

 M. rr. November: N. of Jutland and at Vinga not rare; M. and V. rather common. 

 December: M. and V. c. 



C. constrictus Gran. • — January: M. r. February: V. very common. October: M. 

 rr, V. -\-r. November: N. of Jutland and at Vinga r; M. not rare, V. rather common. 

 December: M. not rare, V. rather common. 



C. contortus Schutt. — February: V. r. March: from 56° 33' N. 12° 15' E. to M. c. 

 April: N.W. of Jutland r, very common in the Skagerak and at M. May: M. c, V. r. 

 June: V. r. Jidy — August: M. r, V. r. September: M. c. October: M. c, V. r -|-. ^o- 

 vember: N. of Jutland c, M. and V. c, Vinga r. December: M. -f-, V. c. 



C. criophilus Castr. — February: V. r. 



C. curvisetus Cl. — .January: central Skagerak r. April: at 56° — 57° N. 4° — 3° E. 

 common to rare. July — August: M. c, V. r. September: M. ccc. October: M. c, V. -|-. 

 November: N. of Jutland, more or less common to rare; Vinga c, M. and V. cc. De- 

 cember: M. rather common, V. common. 



€. danicns Cl. — January: the central Skagerak r, Vinga c, M. -)-, V. r. Febru- 

 ary: V. r. March: Vinga r. /m/^: M. r. November: Vinga r. December: V. r. 



