CTENOPHORA, NEMERTINEA AND CHAETOGNATHA 107 



It was taken in twenty-eight samples from the Antarctic by the ' Gauss'. 1 



Thalassophyes crystalline, Moser. 

 St. WS 36 ... 1 at 750-500 m. 



Taken in 66° S by the ' Gauss'. 1 



CTENOPHORA 



The general distribution of the Ctenophora is tabulated in Appendix II. They were 

 not taken in large numbers except in March and April 1926, to the east of South Georgia, 

 when Beroe formed an important part of the plankton near to the coast. In the same 

 area in November and December 1926, and in May 1927, only small numbers were 

 taken. The rapidity with which the operations at sea were necessarily carried out in 

 order to complete the survey while suitable weather conditions lasted often prevented 

 the examination of the plankton on the spot, and when examined after a considerable 

 interval of time the frail Ctenophora had often disintegrated so that they could only be 

 recognized as such, further identification being impossible. The majority of those un- 

 identified belonged to Pleurobrachia. 



Beroe and Pleurobrachia were both taken in the Antarctic by the 'Gauss'. 2 



NEMERTINEA 



A single specimen of Pelagonemertes sp. was taken at St. WS 22 at a depth of 1000- 

 750 m., i.e. in the warmer intermediate layer, probably of Pacific origin. It has not pre- 

 viously been recorded in the Antarctic Zone. 



CHAETOGNATHA 



The Chaetognatha were examined by Dr H. F. Bargmann who found the following 

 four species : 



Eukrohnia hamata (Mobius). Sagitta planktonis, Steinhaus. 



Sagitta maxima (Conunt). S.gazellae, Ritter-Zahony. 



Eukrohnia hamata was predominant, and was present at nearly all stations, including 

 those approaching South Georgia from Tristan da Cunha (Sts. 9-12) and those between 

 South Georgia and the Falkland Islands (Sts. WS 67-70), it being equally common on 

 each side of the line of the Antarctic Convergence. It was taken in the N 70 V, N 70 H 

 and N 100 H nets. Its vertical distribution, as sampled with the N 70 V nets, is shown 

 in Fig. 49. Fig. 50 shows the distribution round South Georgia during the 

 December-January survey, 1926-7, and also enables one to compare the numbers 

 present on the same line — the C line — at four different seasons, viz. March 1926, 

 November 1926, December 1926 and May 1927. It is remarkably constant in its 

 numbers throughout the area and at these different seasons. It is most abundant at 

 depths between 250 and 50 m., i.e. in a mixture of the cold Antarctic surface water and 

 that of the warmer water below. Table XVI shows its average depth distribution as 

 shown by the N 70 V nets. Fig. 51 also shows its distribution on the lines approaching 



1 Moser (1925). - Moser (1909). 



