2I l'LAi\KTON-TV["KS. TROPICAL NERITIC I'LANKTDN. 



The temp(M'alurc. of the water that contains Desmo-plankton is 

 high, above 'JO , and the salinity 36 j). m. or more. 



The coast regions of the tropical Atlantic are characterized by 

 a number of more or less hnickish species, of which I give the 

 following list: 



Tropical neritic plankton, nl 



Mean Outside 



Limils '«>"Pe- ^',?"." the 



rature salinity Atlantic 



Temora stylifera 37°S.— 42°N, 22.6 34.93 M.I. 



T. turbinata G'^S.— 18°N. 2l.oo 20.29 P. 



Asterionella notata 18°N.— 40''N. 22.8 35.67 M. 



Biddulphia chinensis ... 7'^N.— 10°N. 27.o 36.oi P 1. 

 Chsetoceros (didym. v.) 



longicruris 29°S.— 49.N. 17.3 35.23 M.R.I. 



C. diversus 29°S.— 40°N. 25.i 34.8* M R. I. 



C. femur 7°N.— 12^N. 265 



Coscinodiscus nobihs 5° S — 6° S. 26.8 27.ii 



Ditylum sol 10°N. 27.2 36.oi I. P. 



Nitzschia pungens 7°N.— 10°N. 26.5 36.oi I. P. 



Rhizosolenia cylindrus ... o^N.— 42°N. 25.3. 34.96 



R. robusta 5° S.— 50°N. 21.o 34.93 M. I. P. 



Skeletonema tropicum ... 29° S.— 10°N. 25.8 35 27 



I call the kind of plankton constituted by these species Tropical 

 neritic plankton (Sign. Xl.) Some of the species falling under 

 that kind have a very wide range of distribution, i. e. have been 

 found off Australia, in the Malay Archipelago etc. 



