KONGL. SV. VET. AKADEMIENS HANDLINGAR. HAND. 34. NO 2. 



2. Summer-forms, or such as occur in July-August. 

 Southern: Northern: 



Pödon intermedius. Acartia longiremis. 



Anomalocera Patersonii. Cytiarocylis denticulata . 



Centra pagt >s typicus. 

 Oithona plumifera. 

 Amphorélla Steenstrupii. 

 Acanthometron quadrifotiuin. 

 Ceratiuni fiirca. 

 C. macroceros. 



3. Winter-forms, or such as occur in November (February). 



Southern : Northern : 



Acanthochiasma fusiforme. Lhnacina balea. 



Distephanus speculum. (Acartia longiremis.) 



Halosphcera viridis. Dinophysis acuta. 

 Ceratium bucephalus. 



C. Forms that occur in the spring above the 100-metre plateau, in the 

 summer or winter above the 50-metre plateau. 



1. Occurring in the summer above the 50-metre plateau: 



Southern : Northern : 



Evadne Nordmannii. Calanus jinmarchicus. 



Acartia Clausii. Centropages hamatus. 



Oithona similis. Temora longicornis. 



Ceratiuni longipes. 



2. Occurring in the autumn or spring above the 50-metre plateau: 



Southern : Northern : 



Paracalanua pannis (November). Pseudocalanas elongatus (Winter). 



Ceratiuni fusus (Jan., Febr.). Fungella arctica (Febr.). 



Diplopsalis lenticula (Nov.). Chcetoceros debilis (Spring). 



Rhizosolenia styliformis (Nov.). Coscinodiscus coneinnus (Sept.). 



C. radiatus (Nov.). 

 C. excentricus (Nov.). 



D. Forms, which occur chiefly in the eastern part of the North Sea. 



Fritillaria borealis. — Febr. Metridia hiberuica. — Febr. 



Clione lhnacina. — Jan. Pleurobrachia pilen*. — Jan.. April. 



Po don Leuckarti. — May. Ptychocylis acuta. — Jan., Mardi. 



K. Sv. Vet. Aknd. Himdl. Hand 34. N:o 2. ;> 



