96 DISCOVERY REPORTS 



being a silvery grey. This species has a very wide range in depth and is often common 

 in comparatively shallow water. It is rather noteworthy therefore that only one record 

 (St. WS 507 a) is from 572 m., all the others being from depths between 2582 and 



4344 m. 



Genus Tolypammina, Rhumbler, 1895 



180. Tolypammina vagans (Brady) (F 100) (SG 125). 



Twenty-six stations: 161, 164, 170, 175, 177, 180-2, 190, 195, 377, 383, 384; WS 468, 469, 482, 

 494A, 494B, 497, 498, 505, 514, 516, 517, 523, 555. 



The species is frequent or common wherever material suitable for the attachment of 

 a sessile organism is abundant, notably at Sts. 177, 181, 182, 190, 384, WS 469, 482 

 494B. At other stations it is rare and the specimens are very small, in conformity with 

 the size of their bases of attachment. The stations cover all ranges of depth. Wiesner 

 (W. 193 1, FDSE, p. 94) records three species from the Antarctic, T. schaudinni, 

 Rhumbler, T. frigida (Cushman) and T. hedrix, n.sp., Rhumbler, but reports T. vagans 

 only from extra-Antarctic stations. I regard his three forms as mere variations of the 

 protean T. vagans, and have not separated them. 



Genus Ammodiscus, Reuss, 1861 



181. Ammodiscus incertus (d'Orbigny) (F loi) (SG 126). 



Forty-three stations: 170, 171, 175, 177, 180, 181, 186, 190, 191, 194-6, 202, 203, 360, 363, 366, 

 383, 385; WS 201, 203, 205, 383, 393, 468, 469, 471, 472, 479, 480, 482, 485, 487, 488, 494A, 498, 

 502, 511, 512, 514, 516, 552, 555. 



Almost universally distributed in the area, and at all depths between 100 and 4845 m. 

 Most of the specimens are small, and vary considerably between very neatly coiled and 

 typical shells and those showing a tendency to irregular coiling. These latter, as in South 

 Georgia, pass imperceptibly into Glomospira gordialis. The typical form is common but 

 small at St. 177, larger but rare at Sts. WS 468, 494 a. At most other stations it is rare 

 or very rare. All the specimens seen were microspheric except for two megalospheric 

 specimens (= Ammodiscus tennis, Brady, 1884, FC, p. 332, pi. xxxviii, figs. 4-6) found 

 at St. WS 555 in 3850 m., where the microspheric form was also observed, and a single 

 megalospheric specimen at St. WS 469 in 3959 m. The microspheric form was not 

 recorded at this station. These data indicate that, in this species at least, the megalo- 

 spheric form is extremely rare and can play only a secondary part in the propagation 

 of the species. 



Genus Ammodiscoides, Cushman, 1909 



182. Ammodiscoides turbinatus, Cushman (Plate III, fig. 19). 



Ammodiscoiiles turbinatus, Cushman, 1909, A, p. 424, pi. xxxiii, figs. 1-6. 



Ammodiscoides turbinatus, Cushman, 1918, etc., FAO, 1918, p. 98, pi. xxvi, figs. 3-6, pi. xxxvii, 



figs. 1-6. 



One station: 175. 



A single specimen from 200 m. in the Bransfield Strait, South Shetlands, is probably 

 referable to Cushman 's genus, which he separated from Ammodiscus because the early 



