AMPHIURIDAE 277 



hermaphrodite or female only, and the specimens having been dried, it is now too late 

 to ascertain it. 



No doubt the species is closely related to A. tomentosa, Lyman, as Koehler has 

 noticed ; but I think it preferable to retain it as a separate species, not to regard it merely 

 as a subspecies of tomentosa, as does Hertz — the more so as our knowledge of the typical 

 tomentosa is not very satisfactory. 



Amphiura dilatata, subsp. Gaussi, Hertz 



Amphiura dilatata, subsp. Gaussi, Hertz. 1926. Deutsche Siidpolar-Exped. Ophiuroiden, 

 p. 32, Taf. vi, figs. 5-6. 

 St. 27. IS. iii. 26. West Cumberland Bay, South Georgia, no m. i specimen. 

 St. 42. I. iv. 26. Off mouth of Cumberland Bay, South Georgia, 120-204 m. 2 specimens. 

 St. 45. 6. iv. 26. 27 miles S 85° E of Jason Light, South Georgia, 238-270 m. 4 specimens. 

 St. 144. 5. i. 27. Off mouth of Stromness Harbour, South Georgia, 155-178 m. 4 specimens. 

 St. 148. 9. i. 27. Off Cape Saunders, South Georgia, 132-148 m. i specimen. 

 St. 152. 17. i. 27. 53° 51' S, 36° 18' W, South Georgia, 245 m. i specimen. 

 St. WS 33. 21. xii. 26. 54° 59' S, 35° 24' W, South Georgia, 130 m. 2 specimens. 



These specimens in general agree very closely with Hertz' A. dilatata, subsp. Gaussi, 

 of which I have had a pair of cotypes for comparison. It may be mentioned that small 

 primary plates are sometimes distinct on the disk — the scales being on the whole 

 scarcely as fine as in the type — and that the shape of the buccal shields varies to some 

 degree, from rounded triangular, as shown in Hertz' text-fig. 10, p. 32, to more elongate, 

 with a rounded outer lobe. The arm spines usually reach high up on the dorsal side, 

 leaving — particularly in the proximal part of the arm — only a rather narrow median 

 space free. 



Probably these differences indicate that these specimens represent a local variety, but 

 for the present there seems to be no reason for giving it a separate name. This subspecies, 

 like the typical dilatata, Lyman (or rather atlantica, Ljungman), is not viviparous, and 

 it has separate sexes. The gonads, when filled with ripe sexual products, are large and 

 very distinctly seen through the thin, naked skin of the ventral interradii ; often the skin 

 has ruptured on preservation, the gonads protruding through the ruptures. The eggs are 

 rather small and numerous, indicating that this species may not improbably have a 

 pelagic larva of the Ophiopluteiis type. 



The specimen from St. 27 is regenerating the disk, which, as in other Amphiuras 



with naked ventral interradia (e.g. the North Atlantic Amphiura filiformis), is liable to 



be lost. 



Amphiura Joubini, Koehler 



} Amphiura polita, Koehler, 1901. Result. Voyage 'Belgica'. Echinides et Ophiures, p. 29, 



pi. vii, figs. 49-50; viii, fig. 51. 

 Amphiura Joubini, Koehler, 1912. H^ Exped. Antarct. Fran9aise. Echinodermes, p. 132, 



pi. xi, figs. 9, 13. 

 A. Joubini, Mortensen, 1925. On a small collection of Echinoderms from the Antarctic Sea. 



Arkiv for Zoologi, xvn. A, 31, p. 2. 

 A. Joubini, Grieg, 1929. Some Echinoderms from the South Shetlands. Bergens Mus. Arbok, 



1929. 3. P- 7- 



