248 DISCOVERY REPORTS 



meter, whereas the gonads of a specimen of 8-5 mm. diameter appear to be all female. 

 A gonad from a specimen of 14 mm. diameter is purely male. The indications thus 

 are that this species is a proterogynic hermaphrodite. 



It may be mentioned that there is only one young one, more rarely two, at a time in 

 the bursae, and rarely in more than two to three bursae at a time, in conformity with 

 the fact that rarely more than three to four young ones are found attached to the 



females. 



In some cases I found gonads only along the adradial side of the bursae. 



Some of the specimens from South Georgia are infested by a parasitic organism, 

 probably referable to the Copepod genus Ophioika, described by K. Stephensen from 

 an Ophiacantha from the Bali Sea {Some new Copepods, parasites of Ophhirids and 

 Echinids. Papers from Dr Th. Mortensen's Pacific Exped., lxiv (Vid. Medd. Dansk 

 Naturh. Foren., 93), 1933, p. 205). The parasite does not castrate its host ; I have found 

 young ones in the bursae in a specimen infested with the parasite. A couple of speci- 

 mens from Sts. 170 and 190 are infested by an ectoparasitic Copepod of the genus 

 Cancer illopsis (?), attached on the dorsal side of the arms, close to the disk. 



M. Hertz {op. at., 1926) has established a variety heptactis for the Kerguelen speci- 

 mens, founded on the fact that an 8-rayed specimen is carrying a 7-rayed young one, all 

 the specimens on the whole being 7-rayed with the exception of only two 8-rayed 

 specimens. The 7-rayed condition thus appears to be hereditary in the Kerguelen form, 

 which is taken to necessitate a separate subspecies for this form. Evidently, however, 

 Dr Hertz has forgotten that Studer ( tjber Echinodermen aus dem antarktischen Meere, ges. 

 a. d. Reise S.M.S. 'Gazelle'. Monatsber. Akad. Berlin, 1876, p. 460) had already 

 established a variety kergtielensis for the Kerguelen form ; if this form then deserves to 

 rank as a subspecies (which I rather doubt), its name must be kerguelensis, the name 

 heptoctis of Hertz falling directly into synonymy therewith. 



As for the specimens in the present collection 6-rayed and 7-rayed specimens are 

 about equally common. One may find 6-rayed young ones on 7-rayed specimens 

 (whereas the inverse case, 7-rayed young ones on 6-rayed specimens was not observed). 

 Here the number of the arms is decidedly of no classificatory value whatever. As for 

 the 5-rayed specimens, cf. below under the var. pentactis. 



Ophiacantha vivipara, var. pentactis, n.var. 

 (PlateVII, figs. 3,4) 



St. 170. 23. ii. 27. Off Cape Bowles, Clarence Island, 342 m. 3 specimens. 



St. 187. 18. iii. 27. Neumayr Channel, Palmer Archipelago, 259-354 m. 5 specimens. 



St. 190. 24. iii. 27. Bismarck Strait, Palmer Archipelago, 93-130 m. 3 specimens. 



St. 599. 17. i. 31. 67° 08' S, 69° 06' W, 203 m. I specimen. 



In his work on the Echinoderms of the IP Expedition Antarctique Fran9aise 

 ('Pourquoi-Pas?') Koehler has figured (pi. xi, i) a large five-armed specimen under 

 the name of O. vivipara ; he regards this five-armed form as simply identical with the 

 normally 6-7-rayed O. vivipara. Particularly he emphasizes the fact that there are all 



