ASTRORHIZIDAE 71 



104. Thurammina compressa, Brady. 



Thurammina compressa, Brady, 1879, etc., RRC, 1879, p. 46, pi. v, fig. 9; 1884, FC, p. 324, 



pi. xxxvii, fig. I. 



T}n4ratnmina papillata var. compressa, Heron-Allen and Earland, 1912, etc., NSG, 1917, p. 545, 



pi. xxvii, figs. 2-8. 



Thurammina compressa, Cushman, 1918, etc., FAO, 1918, p. 73, pi. xxviii, fig. 9. 

 Four stations: 170, 175, 385; WS 472. 

 A single specimen at each station, the best at St. 175, but none very typical. 



105. Thurammina cariosa, Flint. 



Thurammina cariosa, Flint, 1899, RFA, p. 278, pi. xxii, fig. 2. 



Thurammina papillata var. cariosa, Heron-Allen and Earland, 1912, etc., NSG, 1917, p. 550, 



pi. xxix, figs. i-ii. 



Thurammina cariosa, Cushman, 1918, etc., FAO, 1918, p. 72, pi. xxviii, fig. i. 



Five stations: 170, 177, 181 ; WS 488, 494A. 



Several very good and typical specimens were found at St. 170, but only single 

 examples at the other stations. 



106. Thurammina spumosa, sp.n. (Plate IX, figs. 14-19). 

 Seven stations: 175, 180-2; WS 482, 507B, 517. 



The test, w^hich is irregularly spherical in shape, consists of two parts, an inner spherical 

 shell and its outer vesicular covering. The inner sphere is composed of fine sand grains 

 and ferruginous cement ; it is firmly built, rough externally and with a few slightly pro- 

 jecting tubes. Internally it is smooth and polished, and has a few pits which mark 

 openings passing through the wall of the sphere to the external tubes. Surrounding the 

 sphere is an external spongy covering, consisting of extremely fine sand grains without 

 visible cement, enclosing vesicular cavities, which are very large in the proximity of the 

 sphere and decrease in size towards the surface, which is a homogeneous layer of very 

 fine sand drawn out into a large number of vesicular cusps. The spongy external 

 covering is thick, a perfect test being about twice the diameter of its inner sphere. It is 

 very fragile, and most of the specimens found are in a greater or lesser stage of dis- 

 integration of the outer covering. Diameter of inner sphere about o-6-o-8 mm. ; of an 

 entire and perfect test about 1-5 mm. 



Frequent at Sts. 175 and 181; rare at St. 182; single specimens only at the other 

 stations. The depths range between 100 m. at St. WS 482 and 2770 m. at St. WS 517, 

 but the last is exceptional. All the stations are in the Bransfield Strait and Palmer Archi- 

 pelago, except St. WS 507 b, which is far away in the south of the Bellingshausen Sea. 



T. spumosa is a very remarkable organism, and quite unique in the development of its 

 external vesicular coating, the purport of which is not apparent. It is probably a de- 

 velopment from T. cariosa, Flint (No. 105), but cannot be confounded with that species, 

 even in a denuded condition. The outer "cavernous" layer of T. cariosa, referred to by 

 Flint in his description of that species, is thin and equally distributed over the surface 

 of the sphere. The vesicles in that species also are usually quite small, though varying 

 in diff"erent specimens. But even the "specimen with coarsely vesiculated cavernous 



