LITUOLIDAE 93 



There is even more range of variation in construction than occurs in the type species. 

 Most of the specimens are roughly constructed and the rectiHnear series is well de- 

 veloped, ranging between four and ten chambers. Usually the rougher the construction 

 is, the shorter the test. An abnormally long specimen with fifteen chambers in the 

 uniserial portion, found at St. WS 472, is very smoothly built, with an excess of cement. 

 Typical short and roughly constructed specimens were found at the same station. 

 Similar organisms were found in the Ross Sea by the Terra Nova Expedition, and 

 figured as "pauperate" specimens of Haplophragmoides aggliitinans, so the variety 

 would appear to be constant in the Antarctic. 



172. Ammobaculites americanus, Cushman (F 97) (SG 117). 

 Eight stations: 385 ; WS 469, 474, 495, 505, 515, 516, 555. 



Curiously rare as compared with its abundance in the South Georgia area. Even the 

 few specimens found were small and pauperate; the best were at Sts. WS 469 and 495. 



173. Ammobaculites tenuimargo (Brady) (SG 120). 

 Two stations: 360; WS 403. 



A single small specimen at each of these deep-water stations. 



174. Ammobaculites foliaceus (Brady) (SG 121). 



Thirty-one stations: 177, 360, 365, 383, 384, 386, 387; WS 199, 201, 204, 386, 395, 400, 471, 473, 

 474, 483, 484, 494A, 496, 497, 502, 506, 507 A, 507B, 511, 512, 515-17, 555. 



Generally distributed over the entire area but never present in any numbers, and at 



most stations rare or very rare. The stations show a wide range in depth between 512 m. 



at St. WS 515 and 4773 m. at St. 386. Depth does not appear to influence structure 



much, although as a rule specimens from stations under 1000 m. are thinner and more 



neatly constructed of fine material than those from deeper water, which are often of 



rougher construction, sometimes incorporating a few larger sand grains which spoil the 



symmetry of the tests. Particularly neat and thin specimens were found at the series of 



stations WS 502-507 b. The species was most frequent at Sts. WS 199 and 516, both in 



deep water. At many of the deeper stations, especially Sts. WS 199, 386, 473, 502, 517, 



555, the spiral portion of the test shows a tendency to become inequilateral, one face 



being more or less concave and the other convex. When this inequilateral growth extends 



over the whole test it forms a very striking variety which seems deserving of varietal 



distinction. 



175. Ammobaculites foliaceus var. recurva, var.n. (Plate III, figs. 14 17). 

 Ten stations: 360, 362; WS471, 472, 502, 503, 505, 517, 552, 553. 



The type species is quite flat ; the variety differs only in the fact that the outer edge is 

 incurved towards the face of the test. As noted under the description of A. foliaceus, 

 some specimens from the deeper stations exhibited an inequilateral structure of the 

 early spiral portion, becoming normally flat in the extended stage. In well-marked 

 specimens of the variety recurva this curling over of the outer edge is continuous 

 throughout growth, the fully developed test presenting quite a distinctive appearance, 

 being deeply concave on one face and convex on the other. The variety appears to be 



