94 DISCOVERY REPORTS 



This species has been minutely described and elaborately figured by Koehler, who 

 separated the extremes of variation under two specific names. The anomalies of distribu- 

 tion apparently raised no question since he recorded the two "species" from the same 

 dredge haul. 



It is perfectly apparent from the fine series under observation that we have an 

 Antarctic species which has practically the same geographic distribution as Bathybiaster 

 loripes obesus. Specimens with shorter superomarginal spines and referable to forma 

 charcoti are found at South Georgia where the long-spined form also occurs. The latter 

 also occurs in the high Antarctic localities, such as the Palmer Archipelago, Ross Sea, 

 and latitude 65° 06' to 66° 55' S, longitude 96° to 145° E (type series of longispinus). At 

 one of the stations in this area, together with longisphms, charcoti was dredged. 



While the extremes are as Koehler has described them, there are intermediates which 

 are with difficulty assigned to either forma. Perhaps this is another way of saying that 

 both formae are variable. For instance, there is as much latitude of variation between 

 figs. 6 and 8, pi. 12 (Koehler, 1920) representing longispinus as there is between the same 

 fig. 6, and fig. 2, pi. 8 (Koehler, 191 2) representing charcoti. Also, the contrasting figures 

 given by Koehler (1920, pi. 51, fig. 5 , c/zarco// and fig. 6, longispinus; pi. 52, fig. i, charcoti 

 and fig. 2, longispifiiis) represent the very extremes of difference. In the Discovery 

 collection are examples connecting these two extremes. No sharp line of distinction can 

 be drawn separating two species, or even two formae of the same species. 



Colour notes. St. 1952, large specimen, bright pink above, yellow below. St. 1957, 

 abactinal surface pale delicate pink, inclining to delicate purple towards and at centre. 



Type locality. Booth-Wandel Island, south of Palmer Archipelago. Paratypes from 

 Wincke Islands and Briscoe Islands. 



Distribution. Circumpolar. In the western hemisphere: Briscoe Islands, Wandel 

 Island, Palmer Archipelago, South Shetlands 30-75 m., mud, pebbles, rocks, grey mud 

 (Koehler); 160-335 m. ('Discovery'). Clarence Island 242 m., rock ('Discovery'). 

 South of South Orkneys, 1775 fathoms (Koehler). South Sandwich Islands (' Discovery '). 

 South Georgia, 75-310 m., stones, clay (Koehler); 91-270 m., grey mud, stones 

 ('Discovery'). 



Eastern hemisphere: Area comprising 92° 10' to 145° 21' E and 65° 06' to 66° 55' S, 

 60-325 fathoms (Koehler). Bouvet Island, 357-377 m. ; Ross Sea, 351 m. (' Discovery'). 



Family BENTHOPECTINIDAE VerriU 



Genus Pontaster Sladen 



Pontaster Sladen, Narr. Challenger Exp., i, 1885, p. 610; 1889, p. 23. Type Astropecten tenuispinus 

 Diiben & Koren. — Ludwig, 1910, p. 447. 



Pontaster planeta Sladen 

 Pontaster planeta Sladen, 1889, p. 30, pi. 10, figs, i, 2; pi. 13, figs, i, 2.— Ludwig, 1910, p. 447. 



St. WS 821. South of West Island, Falkland Islands, 52° 55!' S, 60° 55' W, 351-367 m., i speci- 

 men. 



