GOPALAKRISHNAN: ZOOGEOGRAPHY OF NEMATOSCELIS 



Nematoscelis tenello 



- 24% OF THE SAMPLE 



* 25 - 49% 



A >50% 



Figure 14. — Distribution of Nematoscelis in the Atlantic Ocean based on plankton samples: b - N. 



tenella and A^. gracilis. 



cal and oceanographical differences between these 

 two parts of the Indian Ocean were discussed by 

 Panikkar and Jayaraman ( 1966). Throughout the 

 year N. gracilis old form maintains spawning 

 populations in these two areas. 



Nematoscelis gracilis new and old forms, A^. 

 microps, and A^^. tenella are part of the faunistic 

 assemblage between lat. 0° and 10°S. The occur- 

 rence of A/^. gracilis new form in the mid-Pacific 

 agrees with the distribution of Euphausia 

 pseudogibba and Thysanopoda subaequalis in the 

 zone lat. 10°-20°S (cf Brinton, 1962:212). South 

 of lat. 25°-30°S, N. gracilis is replaced by A'^. atlan- 

 tica. Other species of this zone are Euphausia 

 brevis, E. mutica, Stylocheiron suhmii, and 

 Thysanopoda subaequalis. In the Indian 

 Ocean all of these central species, including N. 

 atlantica, occur only in the Southern Hemisphere. 



ISO" :30- 



Figure 15. — All known records of Nematoscelis lobata. 



1067 



