92 DISCOVERY REPORTS 



readily distinguished by the appearance of the umbilical recesses. In Haplophragmoides 

 scitidus the growth being planospiral and evolute, the umbilici are well-marked de- 

 pressions of equal depth on either face. In Reciirvoides contortus, on the other hand, the 

 umbilicus on one face is often deeply depressed, while on the other the umbilical space 

 is either flat or slightly convex. The convexity marks the peripheral edge of the last con- 

 volution before the change in the axis of coiling. Horizontal sections show that the early 

 convolutions are coiled round an axis set at an angle of approximately 90° to the plane 

 of subsequent convolutions. In the megalospheric form a large proloculus is followed 

 by a single convolution of about seven chambers ; the axis of coiling then changes and a 

 further 1-2 convolutions in the new plane completes the test. In the microspheric form 

 there are apparently two or more convolutions before the plane of coiling changes. 



R. contorttis is one of the most widely distributed species, being found in all the areas 

 between 50-4224 m. It favours moderate depths and is often very common, notably at 

 Sts. 170, 175, 177, 196, 363; WS 383, 386, 483 and 494A. Large specimens attain a 

 diameter of about i -o mm. 



Genus Ammobaculites, Cushman, 1910 



170. Ammobaculites agglutinans (d'Orbigny) (F 96) (SG 116). 



Seventeen stations: 169, 177, 196, 369, 386; WS 403, 469, 471, 472, 494 A, 495, 502, 503, 516, 517, 



552, 553- 



Generally distributed over the entire area but usually rare or very rare. It is, how- 

 ever, frequent and typical at Sts. WS 471, 516 and 552. The specimens are of the North 

 Atlantic form figured by Brady (B. 1884, FC, pi. xxxii, figs. 20, 24), though the uniserial 

 chambers are rarely developed to the extent of his fig. 20. There is the usual wide range 

 of variation in the construction of the test, which is often very rough. At Sts. 177 and 

 369 dark volcanic angular sand grains give a very unfinished appearance, and immature 

 specimens of this construction are not easily separated from Haplophragmoides rotulatiis. 

 The depths range between 720 m. at St. 196, where only two small specimens were 

 found, and 5029 m. at St. WS 553, where very good examples were obtained. 



171. Ammobaculites agglutinans var. filiformis, var.n. (SG 116) (Plate III, figs. 11-13). 



Haplophragmimn agglutinans {pars), Brady, 1884, FC, pi. xxxii, figs. 22-23. 

 Haplophragmimn agglutinans, Sidebottom, 1918, FECA, p. 14, pi. ii, fig. 10. 

 Haplophragmiu?n agglutinafis , Heron-Allen and Earland, 1922, TN, p. 97, pi. iii, fig. 15. 

 Ammobaculites agglutinans {pars), Earland, 1933, SG, p. 79, pi. ii, fig. 22. 



Twenty-five stations: 177, 360, 362, 373, 383, 386; WS 199, 203-5, 400, 469, 471, 472, 474, 479, 

 498, 502, 503, 506, 513, 515-17, 552. 



The variety agrees with the type species in practically all respects except its minute 

 size, and was described and figured, under the specific name only, in the South Georgia 

 report (SG 116). But its occurrence in company with the typical species at ten stations, 

 without specimens of intermediate size connecting the two forms, and still more its 

 occurrence at seven other stations where the type species was not found at all, have 

 decided me to give it a varietal name. It is frequent at Sts. 360, WS 471, 472, 516, but 

 rare elsewhere. Most of the records are in deep water. 



