GORGONOCEPHALIDAE 237 



The very rich material of A. Agassi zii collected by the ships of the Discovery Com- 

 mittee gives us a much better idea of what a splendid form this Gorgonocephalid is 

 than could be gathered from the specimens hitherto known. The largest of these, 

 collected by the Australasian Antarctic Expedition (cf. Koehler, op. cit., 1922), did not 

 surpass a diameter of disk of 36 mm. — in the present material the largest specimen 

 measures 60 mm. in diameter of disk, others measuring some 45-55 mm. in diameter. 

 In these large specimens the radial ribs are generally very conspicuous, though de- 

 pendent to some degree on the preservation, specimens with the disk somewhat swollen 

 having them much less conspicuous than those with the disk flattened. The latter case 

 particularly holds good of the largest specimen (Plate V, fig. 2), which, indeed, gives 

 much the impression of being senescent. The arms in these large specimens are very 

 powerful, some 11 mm. wide, 13 mm. high, and have a very snake-like appearance. 

 About the length of the arms in these large specimens it is not possible to give any 

 definite statements, because the arms are very much coiled up and in most cases broken. 

 But in a specimen 22 mm. in diameter of disk with the arms uncoiled I find the arm 

 length to be no less than ca. 400 mm. This does not necessarily imply that in the larger 

 specimens the arms are correspondingly longer, for in a specimen of ca. 25 mm. diameter 

 the arms do not much exceed 300 mm. in length. (Koehler states that the arms of his 

 specimen of 36 mm. diameter of disk were more than 320 mm. in length ; evidently they 

 were broken, so that it is unknown by how much they exceeded that length.) It would 

 appear that there is considerable variation in the length of the arms, though not in the 

 arms of the same specimen, such as is characteristic of Asteronyx. 



In specimens with the disk flattened there is generally a sharp edge along the inter- 

 radii, recalling the belt of marginal plates of Gorgonoceplmlus. There are, however, no 

 conspicuous marginal plates ; on removing the grain-covering one finds the scales here 

 not much larger than the scales underlying the granules of the disk; it is mainly the 

 folding of the skin that produces this sharp edge. 



The primary plates of the disk are usually distinct in the young specimens, as re- 

 presented by Koehler {op. cit., 1908, pi. xiii, fig. 120); but herein there is a good deal 

 of individual variation. 



I have opened a couple of specimens in order to see what they feed on. Remnants of 

 Crustaceans, Copepods and what was probably a Hyperiid were found and in one 

 specimen there was a rather large lump of jelly of uncertain origin. It appears that the 

 species feeds on plankton organisms, which it most probably catches with the slender 

 distal part of its arms. The eggs are small and numerous, indicating perhaps a free- 

 swimming larval stage. 



Astrochlamys bruneus, Koehler 



(Plate VII, fig. 8) 



Astrochlamys bruneus, Koehler, 1912. IP Exped. Antarct. Fran9aise. Echinodermes, p. 143, 



pi. xi, figs. 3, 4, 6, 7, 14, 15. 

 A. bruneus, Koehler, 1923. Swedish Antarct. Exped. Asteries et Ophiures, p. 103. 

 A. bruneus, Doderlein, 1930. Deutsche Tiefsee-Exped. Ophiuriden. II, Euryalae, p. 373, 



Taf. i, figs. 3-5 (p. 356, fig. le; p. 363, fig. 14 /, m). 



