98 DISCOVERY REPORTS 



depths range between 50 and 1035 m. All the stations are in a line running south-west 

 from the South Orkneys through the Bransfield Strait to the most southerly station, 

 St. 190, which is to the west of the Palmer Archipelago. 



186. Turritellella laevigata, Earland (SG 130). 

 Five stations: 175, 363 ; WS 468, 481, 482. 



Very rare at St. 363 in 329 m. off Zavodovski Island in the South Sandwich Islands. 

 Rare at Sts. 175 and WS 482, which are in the Bransfield Strait between the South 

 Shetlands and Graham Land, in depths of 200 and 100 m. respectively. A single 

 specimen from 543 m. at St. WS 481, also in the Bransfield Strait, and another from St. 

 WS 468 which is in the Drake Strait, almost in the latitude of Cape Horn and outside 

 the Antarctic convergence. This last record is of particular interest on account of the 

 great depth at the station, viz. 4344 m. All the specimens are good and identical with 

 the South Georgia types. 



Genus Ammoflintina, gen.n. 



Test free, arenaceous, approximately triangular in outline, planospiral and bilaterally 

 compressed. Consisting of a proloculus, part of which in the megalospheric form at 

 least is visible on both faces of the test, and around which the chambers are coiled, three 

 chambers forming a convolution. Number of convolutions one or two. The chambers 

 are V-shaped in transverse section, broad and embracing, narrowing a little towards the 

 oral end. The aperture is large and simple, without lip or tooth. Peripheral edge sub- 

 acute. The wall of the test is thin and fragile, composed of fine mineral grains with much 

 cement ; colour pale brown. 



187. Ammoflintina trihedra, sp.n. (Plate III, figs. 20-23). 

 Three stations: 384, 385; WS 204. 



The description of the genus must suffice for the species, which is extremely rare ; 

 three specimens were found at St. WS 204, one at St. 384 and two at St. 385. All 

 stations are in the deep water of the Scotia Sea and Drake Strait, depths 3328 to 3713 m. 

 Most of the specimens are damaged. As a rule there is only a single convolution of three 

 chambers, but some of the specimens have remains of a second convolution which is less 

 regularly disposed, the test losing its flat planospiral form and becoming polyhedral and 

 irregular. The sutures are distinct and slightly depressed. Viewed as a transparent object 

 the proloculus is large and circular, occupying nearly half the diameter of a test with 

 one convolution. The septa are rudimentary; though well-marked externally, they are 

 found to be mere projections from the inner wall into the tube, which loses very little 

 in diameter at the point of constriction. The plan of growth is reminiscent of Flintina in 

 the Miliolidae, hence the name I give to the genus. 



Maximum diameter up to 0-40 m. 



More material must be studied before the affinities and systematic position of 

 Ammoflintiim can be settled with certainty. My specimens are apparently all megalo- 

 spheric, though the proloculus varies in size. From the nature of the test and the rudi- 

 mentary septation I place the genus among the Ammodiscinae, regarding it as a transition 



