14 P. T. CLEVE. THE PLANKTON OF THE NORTH SEA, THE ENGWSH CHANNEL, AND THE SKAGERAK. 



B. Plymouth: almost the whole year, maximum from the erid of September to 

 the middle of December. 



C. Skagerak: rare in January, February, from June to December. 



Eiiterpe acutifrons Giesbr. — The E. Channel: rare at Plymouth in January to 

 March; common in September- — December at Plymouth, St Vaast and Helder. 



Labidocera WoUastonii Lubb. — Rare in the North Sea, June, at 56° N. 2° E. 

 Skagerak: rare in June; along the coast not rare in September, October. 



Metridia hiberiiica Brady & Robts. — North Sea: March: rare from Firth of Tay 



to 57° 21' N. 2° 27' E. June: rare at 56° 26' N. 4° 13'E. November: not rare SW. of Hanst- 

 holm. Skagerak: rare in January and in July. Along the coast rare in January, June, 

 not rare in November, December. 



Microsetella atlantica Brady & Robts. — North Sea: March: abundant east of 

 Firth of Tay, more or less sparingly scattered through the chteto-region to Skagen. Also 

 above the depression S. of the Dogger Bank. August: rare SW. of Norway and W. of 

 Jutland. November: rare W. of the Danish Peninsula to Skagen. E. of Newcastle. — 

 Plymouth rare in February. Skagerak: rare in July and in October. 



Oithona plumifera Baird. — March: rare N. of the Shetlands. At 6r32'N. 2°3rE. 

 November: at 56°irN. 2°3rE. Skagerak: very rare in January. 



O. similis Claus. — A. North Sea: March: abundant between the Shetlands and 

 Norway, E. of Firth of Tay, more or less sparingly scattered in the whole chaeto-region. 

 Not rare W. of Denmark at 55° N. June: common between the Shetlands and Norway, 

 more or less common from the Firth of Tay to Skagen. Common at 54° 25' N. 5° 37' E. 

 July, August: moi'e or less abundant above the Fisher Bank and from the E. Channel to 

 Skagen. A'oye//(6e/': the same distribution, but rarer. — B. The E. Channel: Plymouth the 

 whole year. St Vaast in November. — Helder from August to November. — C. Skagerak: 

 the whole year, rare June, very common from July to December. 



Paracalanus parvus Claus. — A. North Sea: March: not seen. June: rare from 

 the E. Channel to the north of Holland. July, August: abundant from tlie E. Channel along 

 the south coast to the Fisher Bank and Skagen. November: as before, but also from the 

 north of Scotland to the south of Norway. — B. Plymouth: the whole year, maximum 

 from August to December. C. Skagerak: very rare in January, February, abundant from 

 July to October, November. 



Pseiidocalamis elongatus Boeck. — A. North Sea: March: more or less abundant 

 through the chceto-region, from Firth of Tay and Newcastle to Skagen, also above the 

 depression S. of the Dogger Bank. June: decidedly rarer, chiefly on the 50 metre plateau, 

 common near the E. Channel. July, August: above the Fisher Bank, common above the 

 depression S. of the Dogger Bank. November: continues above the 50 metre plateau. From 



