Farquhak. — On a Neiv Sj^ecies of Ophiuridae. 109 



Art. VI. — Description of a New Species of Ophiuridse. 



By H. Farquhar. 



[Read before the Wellington Philosophical Society, 1st November, 2(995.] 



Plate IX. 



The genus Amphiura, to which the Httle brittle-star which 

 forms the subject of this paper belongs, contains more species 

 than any other genus of the Opliiuroidea, and is found in all 

 parts of the woi'ld, and at all depths. It is not therefore sur- 

 prising to find another species of this cosmopolitan genus in- 

 habiting our waters. The only species hitherto known from 

 New Zealand are Amj)liiura parva, Hutton (Trans. N.Z. Inst., 

 vol. xi., p. 305, 1879), from Dunedin Harbour, and Amphiura 

 lanceolata, Lyman ("'Challenger' Eeport," vol. v., Opkiuroi- 

 dea, p. 133, 1882), dredged by the naturalists of the " Chal- 

 lenger" expedition, off the east coast of the North Island, in 

 700 fathoms water. I now add a third, discovered in my first 

 attempt at dredging in Wellington Harbour, 20th January, 

 1892, and since then every haul of the dredge in deep water 

 has revealed many specimens. They exist in great numbers 

 in all the deeper parts of our harbour — from 10 to 15 fathoms 

 — where the bottom is composed of soft, grey mud, from 

 which they derive their nutriment by extracting the organic 

 matter. I find them always associated with a small heart- 

 shaped sea-urchin — Echinocardium australe {E. zelandicum. 

 Gray) — which evidently delights in the same localities and 

 conditions. 



This species appears to have the peculiar habit of throwing 

 off its disc and renewing it, which has also been observed by 

 Professor Verrill in Amphiura ahdita''- (Annals Nat. Hist., 

 ser. 5, vol. ix., p. 476). All my specimens dredged from 

 January to April had perfect discs, with fully developed scaling; 

 but in a dredging taken on the 14th October, when a large 

 number of specimens were obtained, three of them had no 

 discs at all, the teeth and bases of the arms above being quite 

 bare, showing where the disc had been. The other specimens 

 had discs in different stages of development, some consisting 

 merely of granular skin with impressions where the radial 



* It is well known that several other Echinoderms undergo eviscera- 

 tion and regeneration of the disc and visceral mass — as, for instance, 

 Anteclon rosacea {Ann. and Mag. Nat. Hist., of Sept., 1893, p. 197) — but it 

 has not yet been proved whether this takes place spontaneously or is the 

 result of accident. My observations on Ainjjhiuort rosea seem to indicate 

 that this species does eviscerate spontaneously. Further observation will, 

 however, be necessary to decide tbis point satisfactorily. 



