312 DISCOVERY REPORTS 



Koehler {op. cit., 1912) has suggested that this species is oviparous, in contradistinction 

 to the viviparous O. hexactis. I can confirm this suggestion ; also it has separate sexes, as 

 is usual in non-viviparous Ophiurids. The eggs are small and numerous. It is thus very 

 probable that it has a typical OpJnophiteus larva — the more probable since the viviparous 

 O. hexactis passes through a rudimentary larval stage within the ovary. 



Hertz (op. at., 1927) states that the two species O. hexactis and victoriae "scheinen 

 sich gegenseitig auszuschliessen bzw. zu vertreten". It is true that the areas of distri- 

 bution of the two species appear on the whole markedly distinct, the former being in 

 the main confined to the Kerguelen and the South Georgia regions, the latter mainly to 

 the Antarctic region and the sea round Bouvet Island. But that they do not quite exclude 

 one another appears from the fact that O. victoriae is recorded by Grieg (op. cit.) from 

 South Georgia, where O. hexactis abounds. But it seems that in regard to these two 

 species the same condition prevails as between Ophiiira Sarsi, Liitken, and Ophiopleitra 

 borealis, Koren and Danielssen, in the Arctic seas (cf. Mortensen, 1932, Echinoderms of 

 the Godthdb Expedition. Medd. om Gr^nland, 79, 2, p. 30), viz. that these species do 

 not like each other's company and thus in general exclude one another. 



Grieg's observations {op. cit.) on the year classes shown by this species may be well 

 founded (in contradistinction to his finding year classes in Ophiopleiira borealis and other 

 deep-sea Echinoderms; cf. my work on the ' Ingolf ' Ophiuroidea, p. 95 ; Monograph of 

 the Echinoidea, 11, p. no). 



Ophionotus hexactis (E. A. Smith) 



Ophioglypha hexactis, E. A. Smith, 1876. Description of species of Asteridae and Ophiiiridae from 



Kerguelen s Islands. Ann. Mag. Nat. Hist., 4 Ser., xvn, p. iii. 

 Ophionotus hexactis, Koehler, 1912. IP Exped. Antarct. Fran9aise. Echinodermes, pi. xii, 



figs. I, 3. 

 Ophiura hexactis, H. L. Clark, 1915. Cat. Recent Ophiurans, p. 320, pi. 19, figs. 5-6. 

 Ophionotus hexactis, Koehler, 1917. Echinodermes de Kerguelen. Ann. Inst. Oceanogr., vn, 8, 



p. 61, pi. V, fig. 15. 

 O. hexactis, Mortensen, 1920. On hermaphroditism in viviparous Ophiurids. Acta Zoologica, i, 



p. 16. 

 O. hexactis, Mortensen, 1921. Studies of the development and larval forms of Echinoderms, 



p. 179, pi. xxxii. 

 O. hexactis, Koehler, 1923. Swedish Antarct. Exped. Asteries et Ophiures, p. 125, pi. xiv, 



fig. 10. 

 O. hexactis. Hertz, 1926. Deutsche Siidpolar-Exped. Ophiuroiden, p. 17. 

 O. hexactis. Hertz, 1927. Deutsche Tiefsee-Exped. Ophiuroiden, i, p. 68, Taf. vi, fig. 4. 

 O. hexactis, Tortonese, 1934. Gli Echinodermi del Museo di Tori?io. II, Ofiuroidi. Boll. Mus. 



Zool. Torino, XLiv, p. 43, Tav. vii, figs. 42-6. 

 For the older literature cf. Koehler's work of 1917, loc. cit. 



St. 28. 16. iii. 26. West Cumberland Bay, South Georgia, 168 m. 3 specimens (fragments). 

 St. 39. 25. iii. 26. East Cumberland Bay, South Georgia, 179-235 m. 6 specimens. 

 St. 42. I. iv. 26. Off mouth of Cumberland Bay, South Georgia, 120-204 m. 12 specimens. 

 St. 45. 6. iv. 26. 2-7 miles S 85 ' E of Jason Light, South Georgia, 238-270 m. 10 specimens. 

 St. 140. 23. xii. 26. Stromness Harbour to Larsen Point, South Georgia, 122-136 m. 10 speci- 

 mens (young). 



