90 DISCOVERY REPORTS 



471, 486, 502 and 552 it is frequent, and as the depths at these stations range between 

 200 and 4845 m., depth would appear to have little influence on this species. Never- 

 theless, it may be taken as a general rule that specimens from the deeper stations are 

 larger and more coarsely constructed than those from shallower waters. At the re- 

 maining stations it is rare, frequently represented by single specimens. Two distinct 

 forms occur, often in company, one being long and narrow, the other broad and shorter. 

 They probably represent the microspheric and megalospheric forms, but it was not 

 possible to verify the internal structure in the time available. 



168. Haplophragmoides rotulatus (Brady) (SG 115). 



Nineteen stations: 202, 362, 383, 386; WS 199, 204, 377, 399, 468, 469, 471, 472, 474, 495, 502, 

 503. 552, 553. 555- 



Occurs in the deep water of the Weddell, Scotia and Bellingshausen Seas, and in the 

 Drake Strait, but is never common, the only stations at which it was found with any 

 frequency being WS 495 and 503 in the Bellingshausen Sea. It is essentially a deep- 

 water species ; with the exception of Sts. 202 (909 m.) and WS 399 (738 m.), all the 

 records lie between 2552 and 5029 m. 



Genus Recurvoides, gen.n. 



Test free, arenaceous, composed of several convolutions, each containing many 

 chambers. The convolutions are planospiral and partially embracing but arranged in 

 two series, the axis of winding of the second series being approximately at right angles 

 to that of the first or earlier series. The second series therefore envelops the first, but 

 leaves the peripheral edge of the final convolution of the first series visible on one of the 

 faces as a raised line of chambers, extending across the umbilical portion of the adult 

 test. The umbilical portion of the opposite face is more depressed. Composed of sand 

 grains of varying sizes with a considerable amount of ferruginous cement. Aperture 

 small, on the inner edge of the final chamber, sometimes having protruding lips. 



Recurvoides has many points of resemblance to Haplophragmoides, Cushman, but 

 differs from that genus, which is planospiral throughout growth, in its variable axis. It 

 thus bears much the same relationship to Haplophragmoides as Glomospira to Ammodiscus. 

 Trochammifioides, Cushman, 1910, of which the genotype is Trochammina proteus, 

 Karrer, has sometimes a varying axis but is quite distinctive in its irregular chambering 

 and construction. The genotype is Recurvoides contortus, sp.n., which is based on the 

 specimens recorded and figured in the South Georgia report under the name "Haplo- 

 phragmoides scitiihis, Brady, oval variety" (SG 112 and pi. iii, figs. 11, 12). Their real 

 structure did not become apparent until sections were made. Apart from their oval 

 contour due to the change of axis, which becomes less apparent after more than one 

 convolution of the second series has become completed, specimens of Recurvoides con- 

 tortus and Haplophragmoides scitulus are externally in close agreement, and the two 

 species often occur together. Horizontal sections of the two forms are quite different. 

 That the two organisms are not zoologically related is proved by the fact that both 

 megalospheric and microspheric specimens of each have been found. 



