224 DISCOVERY REPORTS 



Vanadis antarctica and Vanadis longissima 

 (Text-fig. 27, Appendix II) 



V. antarctica, collected only to the south of the Antarctic Convergence, and V. longissima, collected 

 only to the north of this boundary, are considered here together, because they may represent geo- 

 graphical races of one species. Both species are large and were collected only by the N 100 and 

 TYF nets. 



Of the V. antarctica hauls, all but two were made in the Antarctic Surface Water and only the 

 specimen, from St. 1936, was collected north of the influence of Weddell Drift. V. longissima also 

 occurred mainly in the top layers of water, but at St. 2636 one specimen was probably taken in the 

 Antarctic Intermediate Current. 



The very close morphological similarity between V. antarctica and V. longissima and the possibility 

 that they are separated in distribution at the surface by the Antarctic Convergence makes it tenable 

 that they are cold and warm water forms of one species, the cold form inhabiting the Antarctic Zone 

 and the warm the Sub-Antarctic, Sub-Tropical and Tropical Zones. Moreover it is possible that 

 they are not isolated from one another in the deeper Antarctic Intermediate Layer or in the Warm 

 Deep Water, but mix freely in the region of the Antarctic Convergence and are carried to their 

 respective surface habitats by the movements of the water masses. Both species could be carried 

 south in the Warm Deep Water, V. antarctica could circulate northwards in the Antarctic Surface 

 Water and V. longissima northwards in the Antarctic Intermediate Water (Text-fig. 14, p. 207). 

 Clearly, however, not only are more records required from depth in the Antarctic and Sub-Antarctic 

 Zones to indicate the relative densities of the circumpolar populations of both, but the reproductive 

 habits of the species must be investigated before the many problems of the V. longissima-V . antarctica 

 complex can be satisfactorily solved. 



Previous records. Within the Atlantic sector of the Antarctic the only records of V. antarctica north 

 of the Antarctic Convergence are from Monro (1936), from Sts. WS 408 and WS 411. I have re- 

 examined these specimens and consider them to be V. longissima. The Swedish Antarctic Expedition 

 collected one specimen of V. antarctica at 69 51' S., 49 37' W., from a net hauled to the surface from 

 200 m. (Stop-Bowitz, 1951). Baker (1954) reported numerous specimens of V. antarctica from the 

 100-0 m. ' Discovery ' samples within the Atlantic sector of the Antarctic and also demonstrated 

 the circumpolar continuity of the species between these depths. V. longissima was reported by 

 Apstein (1900) from the South Atlantic at three stations between 3 S., 13 W., and 2 S., 

 26 W., and by Monro (1930) from Sts. 287 and 291. 



Tomopteris carpenteri 

 (Text-figs. 28-30, Appendices I and II) 



The endemic antarctic T. carpenteri was collected in all water masses at all explored depths within the 

 Antarctic Zone. This species measures up to 70 mm. in length and occurred mainly in the larger nets. 

 However, in N 70 V samples from the South Georgia Surveys, there were numerous small specimens 

 of T. carpenteri less than 12 mm. in length. These include the smallest specimens of the species ever 

 collected, and I refer to them here as juveniles. All other specimens, none of which measures less 

 than 15 mm., I have defined as adult. This purely arbitrary definition serves to separate the material 

 into two groups. Recognition of maturity in the Tomopteridae depends on the presence of sexual 

 products in the parapodial pinnules, and unfortunately in many of the largest preserved specimens of 

 T. carpenteri these are not visible. 



