OPHIACANTHIDAE 255 



Ophiacantha angolensis var. inermis, n.var. 



St. 279. 10. viii. 27. Off Cape Lopez, French Congo, 5S-67 m. 3 specimens. 



These small Ophiacanthas (2-4 mm. diameter of disk) so strikingly recall O. ango- 

 lensis, described by Koehler in his paper Sur quelques Ophiures des cotes de V Angola et du 

 Cap (Goteborgs K. Vetensk. Vitterh. Samh. Handl., xxv, 5, p. 4, pi. i, figs. 4-5), that 

 one is much tempted to regard them as identical. There are, however, some differences 

 which forbid such a course. In the typical angolensis the small stumps covering the disk 

 terminate usually in three distinct, diverging spinules ; in the present specimens these 

 stumps terminate in a simple point. The arm spines are distinctly thorny in the proximal 

 part of the arms in the typical angoletisis, smooth in the present specimens ; further the 

 buccal shields have in general a more distinct outer lobe in these specimens than is the 

 case in the typical angolensis. Otherwise the resemblance is complete : the shape of the 

 dorsal and ventral arm plates, the strongly moniliform and much convoluted arms, the 

 number of arm spines (5-4), the small tentacle scale, the three simple mouth papillae, 

 the brownish colour. Also the locality and depth (O. angolensis was taken off Port 

 Alexander, Angola, 73 m.) being much the same, the probability is that the differences 

 pointed out are only individual variations. However, since the three present specimens 

 are all alike, I think it preferable to designate them as a variety of angolensis. If, when 

 more material comes to hand, it is found that the characters pointed out here are subject 

 to variation so as not to be reliable for distinguishing between the typical form and the 

 variety, the latter may be withdrawn. 



The director of the Gothenburg Museum, my friend Professor L. A. Jagerskjold has 

 very kindly lent me the type specimen of Ophiacantha angolensis, so that I have been 

 able to compare it with the three specimens in the present collection. 



Ophiacantha (Ophiotreta) sp. 



Ophiacantha Valenciennesi, Koehler, 1908. Scott. Nat. Antarct. Exped. Asteries, Ophiures et 

 Echinides, p. 608. 



St. 399. 18. V. 30. Gough Island, 102-141 m. Some young specimens. 



These specimens, no doubt, are identical with those from the same locality referred 

 by Koehler {op. cit.) to O. Valenciennesi, Lyman. They are all very young, 2-3 mm. 

 diameter of disk, only one of them being as large as 6 mm. diameter of disk. Referring 

 to the discussion of the Atlantic forms designated as O. Valenciennesi given in my work 

 on the Ophiuridae of the " Ingolf " Expedition (1933, pp. 34-7), I find it impossible to 

 identify these young specimens with certainty as O. Valenciennesi (as I had to leave 

 unidentified a similar young specimen from St Helena (Echinoderms of St Helena, 

 1933, p. 440). The proximal spines are not widened or bifid at the point, as usual in 

 the adults of O. Valenciennesi. The colour is a brownish mottled, the arms banded 

 with white and brownish. 



A larger material, particularly of adult specimens, will be necessary for settling the 

 question of the identity of this South Atlantic form of Ophiotreta. 



