254 DISCOVERY REPORTS 



genus Ophiectodia, and if we were to recognize that genus, Ophiodiplax would be a 



synonym of it. But I do not think that genus sufficiently well founded. 



One of the specimens from St. 363 is 6-rayed, but otherwise conforms with the typical 



disjiincta. This species is not viviparous; but the eggs are very large, so that there is 



hardlythepossibilitythatthelarvaOp///o/)/?<to«/Vrec'///rtm,Mortensen, can actually belong 



to it, as suggested in my report on the Echinoderm larvae of the German South Polar 



Expedition, p. 96. 



Ophiacantha antarctica (Lyman) 



Ophioconis antarctica, Lyman, 1882. 'Challenger' Oph., p. 107, pi. xxiii, figs. 1-3. 



Ophiacantha polaris, Koehler, 1901. Result. Voyage 'Belgica'. Echinides et Ophiures, p. 32, 

 pi. iii, figs. 19-21. 



O. polaris, Koehler, 1912. IP Exped. Antarct. Fran^aise. Echinodermes, p. 137. 



Ophioconis antarctica. Hertz, 1926. Deutsche Siidpolar-Exped. Ophiuroiden, p. 40. 



Nan: Ophiacantlia antarctica, Koehler, 1901. Result. Voyage 'Belgica'. Echinides et Ophiures, 

 p. 34, pi. iv, figs. 23-25 { = Ophiacantha disjtincta (Koehler)). 

 St. 170. 23. ii. 27. Off Cape Bowles, Clarence Island, 342 m. 2 specimens. 

 St. 172. 5. iii. 27. Off Deception Island, South Shetlands, 525 m. i specimen. 

 St. 181. 12. iii. 27. Schollaert Channel, Palmer Archipelago, 160-335 "^- ^ specimens. 

 St. 186. 16. iii. 27. Fournier Bay, Anvers Island, Palmer Archipelago, 295 m. i specimen. 

 St. 363. 26. ii. 30. South Sandwich Islands, 329-278 m. 10 specimens. 



Whereas I quite agree with Dr Hertz that Koehler's Ophiacantha polaris is indis- 

 tinguishable from Lyman's Ophioconis antarctica, I cannot agree with her in retaining it 

 in the genus Ophioconis. Without entering here on a discussion of Matsumoto's sub- 

 division of the genus Ophioconis I would merely point out the peculiar character of the 

 teeth in the genotype, O. Forbesi (Heller): broad, rounded, with a clear enamel-like 

 border ; this is so different from the shape of the teeth in O. antarctica : narrow, pointed 

 like mouth papillae, and not enamel-like, that the two species cannot reasonably be 

 referred to the same genus. O. antarctica is clearly an Ophiacantha, of the group desig- 

 nated by Verrill as Ophiolimna. Whether the latter should be maintained as a separate 

 genus or as a subgenus of Ophiacantha is rather a matter of taste. 



This species has separate sexes and appears not to be viviparous. But the eggs are large 

 and yolky, which would seem to indicate that it has direct development, without a pelagic 

 larval stage. In my report on'DieEchinodermenlarven der Deutschen Siid-Polar Expedi- 

 tion', 1913, p. 96, 1 have suggested that the larva Ophiophiteiis irregularis described there 

 (p. 94, Taf. xiii, fig. 2; xiv, fig. 3 ; xv, figs. 1-3) may belong to Ophiacantha antarctica. 

 This is, however, not the present species O. antarctica (Lyman), but the O. antarctica of 

 Koehler, which must henceforth be named O. disjuncta (Koehler). The question whether 

 the said larva may really belong to this latter species is discussed above. 



The fact that several of the specimens in hand have the skin of the disk more or less 

 lacerated (dissolved) indicates a peculiar histological character of the skin which exists in 

 several Ophiurids, particularly among the Ophiomyxids, causing the skin to dissolve when 

 the specimen is left out of the water for a few moments. This is evidently the case also 

 in O. Bairdi, Lyman, the genotype of the subdivision Ophiolimna, to which Ophiacantha 

 antarctica belongs. 



