324 DISCOVERY REPORTS 



Ophiurolepis Wallini, Mortensen 



Ophiurolepis Wallini, Mortensen, 1925. On a small collection of Echinoderms frotn the Antarctic 

 Sea. Arkiv for Zoologi, xvii, A 31, p. 3. 



St. 160. 7. ii. 27. Near Shag Rocks, South Georgia, 177 m. i specimen. 



St. 187. 18. iii. 27. Neumayr Channel, Palmer Archipelago, 259 m. 2 specimens. 



St. 190. 24. iii. 27. Bismarck Strait, Palmer Archipelago, 130 m. i specimen. 



To the original description of this species I would only add that the jaws are generally 

 distinctly sunken in the middle, there being thus a circle of five rather conspicuous 

 depressions round the mouth, just as in Ophiurolepis partita. None of the present 

 specimens in hand have any of the ventral arm-plates divided, as was the case in the 

 type specimen. 



The species appears to have separate sexes and not to be viviparous, like O. partita. 

 Two of the specimens were opened and both were found to be females. There are one 

 or two gonads at the interradial, and one at the adradial side of the genital slit. The eggs 

 are few and rather large, exactly as in O. partita. 



On the whole, this species is closely related to O. partita, from which it is dis- 

 tinguished mainly by the character of the dorsal arm-plates, which are undivided in the 

 present species. 



It would appear further that Koehler's Ophioglypha frigida (Result. Voyage ' Belgica', 

 Echinides et Ophiures, p. 16, pi. v, figs. 31-3) is also a close relation of the present 

 species. I even had a suspicion that they might be identical ; having, however, had an 

 opportunity of seeing the type of O. frigida in the Brussels Museum and of comparing 

 it with a specimen of O. Wallini that I had brought with me, I had to recognize that the 

 two species are distinct. 



Furthermore, it seems evident that the Amphiophiura relegata, described by Koehler 

 in his report on the Ophiuroids of the Australasian Antarctic Expedition (p. 57, pi. 

 Ixxxviii, figs. 1-7) must also be nearly related to O. Wallini and partita. This sounds 

 rather remarkable, since Koehler refers this species to quite a different genus, Amphi- 

 ophiura. However, I think Koehler is mistaken in placing the species in this genus. 

 Judging from his photographic figures — unfortunately very poor — it agrees very much 

 more with O. Wallini and partita.^ By this I do not mean to say that the species 

 relegata should be transferred to the genus Ophiurolepis. As a matter of fact, I rather 

 doubt whether all these species ought properly to be referred to the genus Ophiurolepis. 

 I am strongly inclined to think that they ought to form a separate genus, differing 

 from the typical Ophiurolepis in the much better developed ambulacral pores, and further 

 characterized by the total absence of papillae at the base of the arms. I shall, however, 

 refrain from establishing such a genus at present, as it could hardly be done properly 

 without a complete revision of the large and difficult Ophiurolepis-Homalophiura 



1 After this report was sent to press I received from the Australian Museum, Sydney, a cotype of 

 Koehler's Amphiophiura relegata. Comparison with the types of Ophiurolepis Wallini shows that these 

 two species are, indeed, very closely related, though apparently distinct. 



