DISTRIBUTION OF ANTARCTIC MACROPLANKTON 101 



Metridia gerlachei. On the whole a cold-water species. A peculiarity of its distribu- 

 tion is that it is found in much the largest quantities between the South Shetlands and 

 South Orkneys, along the Orkney-Sandwich ridge, and around the South Sandwich 

 Islands. It is one of the very few members of the macroplankton which are found in 

 any considerable numbers in this region. Possibly its method of reproduction is in some 

 way associated with the bottom or with the conditions found in shoal waters. However, 

 it is to be found in varying quantities everywhere from the convergence to the highest 

 latitudes. It is a species which is often distributed evenly over large areas but which 

 sometimes appears suddenly in exceptionally large numbers. It thus has some tendency 

 to form shoals, or at least to appear in local concentrations, and it must be regarded as 

 a patchy species. 



Haloptilus ocellatus. This species is confined to the coldest water. It has occurred in 

 moderate numbers (ioo to 500 per haul) in the Bellingshausen Sea west of Peter 1st 

 Island and in the eastern Weddell Sea. Occasional specimens are recorded from the 

 Orkney- Shetland region and from the ice-edge near Bouvet Island. There is no evidence 

 to show that its distribution is at all patchy. 



Haloptilus sp. Found everywhere from the convergence to the Bellingshausen Sea, 

 but it is not recorded from the Sandwich or eastern Weddell regions, and has appeared 

 only once in the Orkney- Shetland coastal region. However, it is among the rarer 

 Copepoda, and there is not enough material to form the basis of any definite conclusions. 

 It is perhaps commonest in the warmer parts of the Antarctic. 



Parenchaeta sp. This genus also has a wide distribution, but it is commonest in the 

 warmer parts of the Antarctic. Like Rhincalanus it pervades the whole of the belt lying 

 immediately south of the convergence and is absent only from hauls taken during the 

 daytime. It appears sometimes in the Bellingshausen and Weddell Seas, and is met 

 with in small numbers in Bransfield Strait, in the coastal waters of the South Orkneys 

 and South Shetlands and in the eastern Bellingshausen Sea. 



Heterorhabdus sp. Although this is an uncommon genus it clearly belongs to the 

 warmer parts of the Antarctic water; its distribution seems very similar to that of 

 Calanus simillimus. 



Eucalanus sp. Also clearly typical of the warmer water, but its occurrence is curiously 

 spasmodic. At one time it may be found at every station of a line, say, from South 

 Georgia to the convergence, while at another time none will be caught along a similar 

 line. On the other hand its distribution does not appear to be in any way patchy. 



Euchirella sp. This is one of the rarest of the large Antarctic copepod genera. 

 It has occurred here and there in the warmer water, off South Georgia, in the 

 Bellingshausen and Weddell Seas and in the outflowing Weddell water. We cannot say 

 more than that, as a genus, it is not confined either to the warmer or colder Antarctic 

 water. 



Candacia sp. This is another scarce genus, but it has not been found in the 

 colder regions and is commonest close to the convergence. It is clearly a warm- 

 water form. 



