SCYPHOMEDUSAE 



385 



Hope and north of South Georgia, and one haul (St. 391) is from the south-east of the 

 Falkland Islands. The greatest number of individuals has been collected at this station 

 (391) with twenty specimens of different sizes, and at another rich haul at St. 395 

 (north of South Georgia) there were six specimens. In three localities (Sts. 407, 72, 151) 

 A. chuni has been taken together with A. ivyvillei and Periphylla hyacinthina. The 

 distribution of Atolla chuni is wholly restricted to the sub-Antarctic part of the Atlantic 

 Ocean ; the medusa has not yet been found in Antarctic waters south of the latitude of 

 Cape Horn, nor to the north of 30° S. Comparing the distribution of ^. chimi with that 

 of A. zvvri/lei in the same regions, we find that in both cases most individuals are gathered 

 in the neigJibotirhood of continents or groups of islands. 



5<5 



O ATOLLA CHUNI VANH 

 O PREVIOUS RECORDS 



Fig. 9. Chart showing the distribution of Atolla chuni, Vanhoeffen. 



Vertical distribution (see Table IX). A. chuni is a true deep-sea medusa with the 

 typical pigmentation of abyssal forms. The ' Valdivia' found it in ± 1500 m. depth, and 

 the ' Scotia' in about 2000 m. The ' Discovery' never collected A. chuni in closing net 

 hauls from 800 m. upwards. The most superficial catch was made south-west of the 

 Cape between 800 and 900 m. and between the Cape and Bouvet Island in 850-950 m. 

 In all other closing net hauls the species was present only in depths of 1000-1500 m. 

 The specimens collected with open nets were also found only when nets were used at 

 depths exceeding 1 100 m. All these facts prove A. chuni to be a true component ofBigelow's 

 so-called intermediate fauna. It prefers deeper layers than A. wyvillei. Most striking is 

 the rich catch from St. 391 (south-east of the Falkland Islands) from 1200 to 1300 m. 

 depth, with twenty-one fair individuals, almost the half of the whole. It is a pity that it 



