24 ■ DISCOVERY REPORTS 



this area, although it does not figure in the hst of species found by F. Chapman and 

 W. J. Parr in the material collected by the Mawson Expedition between 6o°-7o° S 

 and 90°-i50°E, or from this Expedition's deep-water Stations between Australia and 

 the Antarctic. It is possible that the species may be found in greater numbers in 

 shallower water nearer the Antarctic coast-line, which would seem a more natural 

 habitat for such a large porcellanous species. As no specimen has ever been found in 

 the Pacific or western area of the Antarctic, the species is probably peculiar to the 

 eastern area between Graham Land and the Kerguelen plateau. 



Until more material is available the real structure of the organism must remain 

 speculative, but after a careful examination of my specimens I am inclined to the belief 

 that the structure is not so complex as Brady thought. He regarded the sphere of 

 Keramosphaera as analogous to the disc of Orbiiolites in structure, but to me the structure 

 seems quite different. If a specimen of Keramosphaera is examined by direct light 

 while immersed in fluid, it shows the chambers filled with air. They present the ap- 

 pearance of unseptate tubes wandering irregularly in all directions, dividing and joining 

 again and passing over and under one another. There is no definite septation visible 

 in the tubes but a slight constriction at intervals, and especially at the point of division. 

 The tubes open on the surface in numerous low arched apertures (Plate I, fig. 9) with 

 slightly thickened lip. These layers of tubules are concentric, for the test when it 

 breaks shows a tendency to separate at the layers, as shown in Rollick's fig. 2 (B. 1882, 

 K, pi. xiii, fig. 2), and in one of my specimens from St. 313. Examination of a 

 fractured surface of the section photographed by Wiesner or even the section figured 

 by HoUick (fig. 3, ut supra), seems to confirm this tubular structure rather than the 

 layers of chamberlets postulated by Brady. If this suggested tubular structure is borne 

 out by further research, the subfamily Keramosphaerinae would probably be found 

 to be nearer akin to the Nubecularinae than to the Alveolininae. 



Keramosphaera is not easily illustrated, and I think the admirable photographs of 

 Wiesner are more truthful than the original drawings of Hollick. They bring out the 

 characteristic blistered surface texture, and show the apertures. 



Family ASTRORHIZIDAE 

 Subfamily ASTRORHIZINAE 

 Genus Astrorhiza, Sandahl, 1857 

 14. Astrorhiza arenaria, Norman. 



Astrorhiza limicola, M. Sars, 1868 {non A. Umicola, Sandahl), LUHD, p. 248; G. O. Sars, 1871, 

 HF, p. 252. 



A. aretiaria, Norman, 1876, V, p. 213. 



A. arenaria, Brady, 1879, etc., RRC, 1879, p. 43 ; 1882, FKE, p. 711 ; 1884, PC, p. 232, pi. xix, 

 figs. 5-10. 



A. arenaria, Pearcey, 1914, SNA, p. 997. 

 One station: 43 2 A. 



Only a fragment, probably referable to this species. 

 Pearcey: 291, 420 (apparently many, A.E.). 



