14 



PLANKTON-TYPES. ARCTIC NERITIC PLANKTON 



plankton-type, Ng. This kind forms a good deal of the .SV>a- 

 plankton of the Skagerak. The mean temperature of the water 

 containing this kind of plankton is, as a rule, low, — 0,6° to 8,9°, and 

 the salinity is usually considerably below 34 p. m. 



The following list contains the species of this kind of plankton: 



Arctic neritic species 



T . .. Mean 



Limits 



tena- 

 Lat. N. 



perature 



Ghone limacina 82°— 42° 3.s 



Limacina helicina 81°— 58°(35) 4.2 



Acartia longiremis 80°— 58° 7.8 



Pseudocalanus elongatus... 79° — 40° 8.9 



Amphorella vitrea 80°— 70° — O.s 



Fungella arctica 80°— 50° 3.5 



Ptychocylis arctica 75°— 37° 6.0 



P. obtusa 8l°— 42° 3.5 



Tintinnopsis karajacensis... 81° — 69° 2.? 



Tintinnus bottnicus 81°— 80° 2.? 



Ceratium hyperboreum 81° — 80° 2.i 



Peridinium catenatum 80° — 73° 3.2 



Dinobryum pellucidum 81°— 68° I.9 



Achnanthes taeniata 80°-57° — O.3 



Amphiprora hyperborea ... 80° — 74° — 0.4 



Chsetoceros bottnicus 80°— 72° —0.4 



C. diadema ...:.' 80°— 40°(6) 6.0 



C. furcellatus 80°— 59°(50) 4.5 



C. socialis 74°— 50° 4.5 



Eucampia gronlandica 78° — 57° — O.2 



Fragilaria oceanica 80°— 63° O.s 



Lauderia fragihs 80° — 59° O.9 



Melosira hyperborea 74°— 75° — O.5 



Navicula septentrionalis ... 80° — 69° 1.5 



Nitzschia- frigida 80° — 74° — 0.4 



Thalassiosira hyalina 80°— 63° l.s 



T. Nordenskioldii 80°— 40° 7.i 



Ng. 



