204 



DISCOVERY REPORTS 



As a fact of morphological interest may be mentioned the coalescing above the arm 

 of the two bursae at each radius in Ophiacantha densispina, a feature previously known 

 only in Ophiomitrella corynephora, H. L. Clark (cf. my Echinoderms of South Africa, 

 p. 332). That the spicules in the bursal wall of this same species of Ophiacantha form 

 inner thorns proceeding into the body cavity is a unique feature ; but, of course, this 

 has more the value of a curiosity. Another interesting fact is the existence of only 

 a single genital slit in each interradius in Amphiiira monorima (cf. p. 274). 



Much more interest, however, attaches to the discovery that a very great proportion 

 of the Antarctic Ophiurids are viviparous. Till now only six of these Ophiurids were 

 known to be viviparous, viz. Ophiomyxa vivipara, Ophiacantha vivipara, O. imago, 

 Amphiiira magellanica, Amphipholis sqiiamata {patagonica) and Ophionotus hexactis. 

 I have found no less than twenty-five more of the Antarctic Ophiurids to be likewise 

 viviparous, namely: 



Astrochlamys bruneus 

 Ophioscolex niitrix 

 O. marionis 



Ophiacantha densispina 

 Ophiomitrella ingrata 

 O. fallilandica 

 Ophiochondrtis stelliger 

 Amphiiira angular is protecta 

 A. microplax 

 A. monorima 

 A. Lymani 

 A. deficiens 

 A. Belgicae 



Ampliiiira Eiigeniae 

 Amphiodia affinis 

 Ophiolebella biscutifera 

 Ophioceres incipiens 

 Ophiozonella falklandica 

 Ophiomages cristatus 

 Ophiosteira antarctica 

 Ophiurolepis Martensi 

 Ophiiira meridionalis 

 O. Rouclii 



Amphiophiura Rowetti 

 A. gibbosa 



We thus know now at least thirty-one Ophiurids of the Antarctic and sub-Antarctic 

 regions to be viviparous. Of the other Ophiurids from this region the following twenty- 

 five species are not viviparous: 



Gorgonocephalus chilensis 

 Astrotoma Agassizii 

 Ophiacantha disjuncta 

 O. antarctica 

 Opliiactis asperula 

 Amphiura a?igularis 

 A. microplax disjuncta 

 A. dilatata Gatissi 

 A. Joiibini 

 A. princeps 

 Amphiopliis acutiis 

 A. peregri?iator 

 Ophiogona Doderleini 



Ophioperla Koehleri 

 Ophionotus victoriae 

 Ophiosteira Senouqui 

 Ophiiiroglypha Lymani 

 Ophiurolepis caritiata 

 O. gelida 

 O. brevirima 

 O. Wallini 

 O. partita 



Homalophiura i?iornata 

 H. inortiata tuberosa 

 Ophiocten amitinum 



The rest of the species are unknown in regard to their sexual character, or the material 

 examined has been insufficient for giving definite information. But it may be regarded 

 as an established fact already that about 50 per cent of the Ophiurids of the Antarctic- 



