36 P. T. CLEVE, PLANKTON-RESEAKCHES. 



Ceratiuin fiirca Dujaudin. ■ — 1901 Januray, V. orr; M. rr. Februari/, V. rro\ 

 Nonv. 63°— 64°N. 0°— 6°E.; 68° N. 13°— 14°E. f;'69°N. 16°— 17°E. c; 70° N. 10° E. r. 

 March, Nonv. 71°— 74°N. 16°— 24°E. + r. April, M. roo. Norw. 69° N. 14°— 18°E. +. 

 May, ror. M. orr. Atl. area 61° N. 5° E., 62° N. 0° E. and 68° N. 13° E. not rare in the 

 west, common in the east. June, M. rr. August, sparingiy W. of Scotland, common N. 

 and E. of Scotland, thence with decreasing abundance to S. Norway, Dogger bank and 

 W. Jutland. Not found in the southern North Sea. Skagerak sparingiy from the central 

 part to the whole Swedish coast. September, V. /■. M. roo. October, V. rrr. M. oor. 

 November, extremely abundant from Firth of Forth and Newcastle to 58° N. 4° E. and 

 Skagen, N. of Dogger bank, less abundant along the Avest coast of the Danish Peninsula. 

 V. + + c. December, V. c + r. M. cro. R.Sg. c. Nh. r. 



1902 January, V. c +. M. er. February, common in the area 58° N. 0° E., 55° N. 

 5° E. and Skagen, more or less sparingiy from the Orkneys to the coast of Holland and 

 S. Jutland. Skagerak everywhere 50 — O m. c to r. May, area between Firth of Forth, 

 Newcastle, 56° N. 7° E., Skagen and Norway, common in the central part, otherwise spa- 

 ringiy. M. o + 0. V. o + r. June, M. +. V. ror. July, M. rrr. V. rrr. The 

 fjords r. — Tp. 



Ceratiinn fnsus Du.jardin. — 1901 January, V. crr; M. rr. February, Norw. 63° 

 — 64°N. 0°— 6°E., 68°— 70°N. 17°— 10°E., common near the coast, rarer in the west. 

 March, Norw. 71°— 74° N. 16°— 24°E. + r. April, V. oro. Norw. 69° N. 14°— 18° E. r. 

 il%, V. rrr. M. rro. Atl. area 61° N. 5° E., 62° N. 0° E. and 68° N. 13° E., common in 

 the est, rare in the west. June, M. or. July, M. ror. August, sparingiy from the Scheldt 

 to Skagen, not rare south of Norway, thence sparingiy to N. Scotland, not rare in Firth 

 of Forth. Central Skagerak to Koster and Gullraarfjord, as a rule sparingiy. Septemher, 

 V. +. October, V. cc +. M. rrr. November, as C. furca, but not so abundant. V. + + +. 

 December, V. c + r. R.Sg. c. Nh. f. 



1902 January, V. r. February, common from S.W. Norway to N. Jutland, not 

 rare in the area 58° N. 0° E., 53° N. 6° E. and Skagen, otherwise sparingiy in the whole 

 North Sea. Skagerak, everywhere r to c. Apiril, M. or. V. oor. May, area 56° N. 1° W. — 

 8° E. and Skagen, abundant W. and N. of Jutland, otherwise sparingiy. Off the coast of 

 Holland. M. rrr. V. or +. June, M. +. V. crr. July, M. + rr. V. ro +. The 

 fjords r. — Tp. 



Ceratiuni horriduni Cleve. — 1901 February, Norw. 63°— 64° N. 0°— 6° E. c to r; 

 68° N. 13°— 14°E. r; 69° N. 16°— 17°E. +; 70° N. 10° E. r. March, Norw. 71°— 74°N. 

 16°— 24°E. c to r. April, Norw. 69° N. 14°— 18° E. r. May, Norw. 61° N. 3°— 5° E. + 

 to r, 68° N. 8° E. +. *) 



Ceratium lineatuiu Ehrenberg. — 1901 January, M. ro. February, V. roo. April, 

 Norw. 69° N. 14°— 18°E. r. May, M. oor. September, V. r. October, V. ror. M. o + r. 



*) Gkan's data. I have united this form with C. longipes. 



