6 DISCOVERY REPORTS 



are each represented by about lOO individuals, namely A^^. orcadense and A'^. brevi- 

 caudatiim. The remaining species of the genus are, as a rule, represented by single 

 specimens or by very small numbers. The family Ammotheidae is represented by over 

 300 specimens, but, with the exception of Achelia parvula, no species is represented 

 by more than twenty-five specimens. Twenty-four species were each obtained only at 

 a single station and all in small numbers. As against this Nymphon brevicaiidatum 

 occurred at twenty-three, and PaUenopsis patagonica at twenty-one stations. 



The depths at which Pycnogonida were obtained rarely exceeded 500 and were 

 usually between 2 and 350 m. 



With regard to geographical distribution, the majority of the species were collected 

 in the Glacial District of the Antarctic Zone^ (Palmer Archipelago to South Georgia, 

 the South Sandwich Islands and Bouvet Island) ; a considerable number occurred only 

 in the Magellan District of the sub-Antarctic Zone, and a few species were found in 

 both districts (see table, pp. 4, 5). 



The ' Discovery ' has done very extensive collecting in the neighbourhood of South 

 Georgia, and the 'William Scoresby' concentrated on the neighbourhood of the 

 Falkland Islands (Magellan District). Although the former is not so very far south of 

 the latter group of islands, the pycnogonidan fauna apparently differs considerably. 

 Of the nineteen species from the Magellan District only six- are also represented from 

 South Georgia and one from the South Orkneys. One species, Colossendeis scoresbii, 

 may prove to be a northern form^ of C. frigida, which, though most commonly found 

 in the Glacial District, is also present in the Magellan District (pp. 4, 5). 



Of the four species collected beyond the northern limits of the sub-Antarctic Zone, 

 two are very near to, if not identical with, sub-Antarctic forms {Tanystyliim pfejferi and 

 Pycnogomim mageUaniciim (?) from Gough Island and Tristan da Cunha). 



Twenty-seven of the Antarctic and sub-Antarctic species have also been recorded 

 from the Ross Sea Area, ten from Kaiser Wilhelm Land and two from the Kerguelen 

 District (see table, pp. 4, 5). It is highly probable that the majority of these forms will 

 prove to be circumpolar in their distribution. 



The decapodous species Pentapycnon charcoti, collected by the 'Pourquoi-Pas?' off 

 the South Shetlands, has not been rediscovered, although Dr S. Kemp was on the 

 look-out for it. 



Breeding season. Ovigerous or larvigerous males of sixteen species were obtained. 

 As far as one can judge, in the absence of records covering all months of the year, the 

 breeding season (assuming that there is a definite season) differs in Antarctic and in 

 sub-Antarctic or Temperate waters. In the Antarctic Zone males were carrying ova or 

 larvae from October to April, usually from December to March (table, pp. 4, 5). In the 

 Magellan District all the ovigerous and larvigerous males were collected in July. In one 



1 See map given by Regan (1914, fig- 2, p. 25). 



2 Nymphon orcadense has also been recorded from South Georgia, in addition to those hated. 



3 Similarly Nymphon biarticulatum may prove to be a more southern form of the common A'', brevi- 

 caudatum (p. 72). 



