8o 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



highly peculiar, special habitats in very different parts of the 

 ocean. Favella is a more generalized genus of more tem- 

 perate waters, especially coastal. Few if any species of 

 Xystonellopsis ever enter neritic environments, this genus 

 being common in the high seas. It is interesting that none 

 of the Xystonellidae enter the Antarctic, although the family 

 has mastered most other seas. 



Twenty-two species are described here. 



Xystonellopsis abbreviata Kofoid and Campbell 



Xystonellopsis abbreviata Kofoid and Campbell, 1929, p. 239, 

 fig. 468. 



The moderately stout lorica, with piilchia-\\]ic form and 

 short pedicel, has a length of 5.1 oral diameters. The oral 

 margin is thin and erect. The suboral band occupies the 

 anterior 0.16 total length and has 3 rounded, subequal rings 

 with diameters of nearly 1.27 oral diameters; these rings are 

 thin, and virtually equidistant, the upper one being a little 

 below the oral rim. The interspaces between the rings are 

 thickened. The bowl below the band is subconical (10° in 

 the upper 0.21 and 38° in the lower 0.16 total length). The 

 pedicel is thick (0.36 oral diameter at the upper end) and 

 tapering (5°), with a slight, aborally truncated skirt at the 

 distal end. The lance is conical (2°) and distally pointed, 

 and has a length of 0.55 oral diameter. 



The wall has a thickness of o.i oral diameter just below 

 the spool, and there are thin laminae which enclose small 

 hexagons in several layers in the spool, radial secondary 

 prisms in a single layer in the bowl, and large hexagons in 

 the skirt and lance. The lumen does not enter the spool, 

 and forms a narrow canal in the lance. 



Length, 275 to 336fi. 



Xystonellopsis abbreviata is much like X. pulchra, but is 

 not so long; its suboral spool is shorter and the pedicel is 

 short. 



Recorded from one station (108) in the North Pacific trade 

 region, in a pump sample taken at 100 meters. Frequency, 

 minimum. 



Temperature, 25?36; salinity, 34.99; density, 23.24; pH, 

 8.23. 



Xystonellopsis acuminata Kofoid and Campbell 



Xystonellopsis acuminata Kofoid and Campbell, 1929, p. 239, 

 fig. 482. 



The moderately tall lorica, with heros-Wke bowl, stout 

 pedicel, and pencil-shaped lance, has a length of 5.56 oral 

 diameters. The oral margin is sharp, with a trace of flare 

 within the upper tenth. The bowl is subcylindrical in the 

 anterior half and conical (14°) in the aboral region, which 

 merges with the pedicel. The lance arises from the barely 

 differentiated skirt; it is pencil-like, 0.5 oral diameter in 

 length, and sharply pointed. 



The wall is nearly 0.08 oral diameter in thickness, and 

 the thin laminae enclose several layers of minute alveoles. 

 On the pedicel are 8 right-twisted (3°) ridges. 



Length, 354 to 4141,1. 



Xystonellopsis acuminata has a clear-cut skirt wholly lack- 



ing in A', dahli. It is not so long as X. heros, and has a 

 pencil-shaped rather than conical lance. Xystonellopsis gaussi 

 has a stouter, conical lance and more definite pedicel. 



Recorded from five stations in the Pacific, as follows: one 

 (35-36) in the Pacific equatorial region, three (112, 113, 145) 

 in the North Pacific middle latitudes, and one (131) in the 

 California region. 



There are i pump sample and 4 net samples, of which i 

 was taken at the surface and 4 at 100 meters. Maximum 

 frequency, 11 per cent at station 112; other records above 

 minimum (2 to 8 per cent) from stations 113, 131; average 

 in net samples, 7.6 per cent. 



Temperature: pump sample i6?58, net samples I2?i2- 

 2i?74 (i8?oo). Salinity: pump sample 34.71, net samples 

 33.36-34.71 (34.24). Density: pump sample 25.00, net 

 samples 24.06-25.31 (24.63). pH: pump sample 8.31, net 

 samples 8.23-8.32 (8.25). 



Xystonellopsis armata (Brandt) Kofoid and Campbell 



Xystonellopsis armata, Kofoid and Campbell, 1929, p. 241, fig. 

 481. 



The rather tall lorica, with contracted lower bowl, ex- 

 panded pedicel, and short, conical lance, has a length of 6.65 

 oral diameters. The oral margin is thin and sharp. The 

 bowl tapers (5°) in the upper 0.48 total length and becomes 

 subconical (30°) in the lower 0.2 total length. The pedicel 

 increases in diameter from the lower bowl (4°) and has a 

 length of nearly 0.32 total length; at its distal end is the 

 squarely truncated, non-expanded skirt. The lance is conical 

 (32°), only 0.5 oral diameter in length, and sharply pointed. 



The wall reaches nearly o.i oral diameter in thickness 

 suborally, and becomes a litde less in the lower bowl. There 

 are comparatively thick, dark laminae, which enclose homo- 

 geneous material. The lumen forms a canal in the lance. 

 The pedicel has 8 subvertical pleats. 



Length, 365 to 410H. 



Xystonellopsis armata resembles X. gaussi, but the pedicel 

 becomes distally wider instead of contracted, and the lance 

 is conical and wide rather than pencil-shaped. It differs 

 from X. heros in having a subconical lower bowl with dis- 

 tinct transition to the pedicel, as well as in being shorter. It 

 lacks the suboral thickening of X. tenuirostris. 



Recorded from twenty-one stations, two in the Atlantic 

 and nineteen in the Pacific, as follows: two (23, 24) in the 

 Adantic equatorial region, two (35, 153) in the Pacific equa- 

 torial region, two (45, 68) in the Galapagos region, three 

 (65, 66, 67) in the South Pacific middle latitudes, two (109, 

 150) in the North Pacific trade region, eight (133, 134, 135, 

 156, 146, 147, 148, 149) in the California region, and two 

 ( 142, 145) in the North Pacific middle latitudes. 



There are 6 pump and 16 net samples, of which 4 were 

 taken at 50 meters and 18 at 100 meters. Maximum fre- 

 quency, 26 per cent at station 67; other records above mini- 

 mum (2 to 25 per cent) from stations 23, 24, 35, 45, 65, 66, 

 68, 109, 135, 142, 145, 146, 148, 150; averages in net samples, 

 1.2 and ii.o per cent in the Atlantic and Pacific, respectively. 



Temperature: Atlantic, net samples 20?99-23?i2 (22?05); 



