82 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



20 per cent at station 145; other records above minimum (4 

 to 6 per cent) from stations 41, 95, 136, 146; average in 

 Pacific net samples, 6.8 per cent. 



Temperature: Atlantic, pump sample 20?32, net samples 

 20?99-24?44 (22?7i); Pacific, net samples i4?55~28?74 

 ( 1 9°54). Salinity: Atlantic, pump sample 36.81, net samples 

 36.04-36.18 (36.11); Pacific, net samples 34.32-35.33 (34-53). 

 Density: Atlantic, pump sample 26.07, net samples 24.42- 

 25.30 (24.86); Pacific, net samples 22.43-26.11 (24.50). pH: 

 Atlantic, pump sample 8.21, net samples 8.14-8.21 (8.17); 

 Pacific, net samples 7.92-8.39 (8.22). 



Xystonellopsis cyclas Kofoid and Campbell 



Xystonellopsis cyclas Kofoid and Campbell, 1929, p. 244, fig. 

 457- 



The fairly short lorica, of general cymatica type, with 

 thickened cylindrical pedicel and long lance, has a length of 

 5.0 oral diameters. The oral margin is thin and spread. The 

 bowl has a ringlike (0.25 oral diameter in width) ledge 

 (1.15 oral diameters in diameter) located just below the 

 anterior 0.1 oral diameter. The bowl below this ledge tapers 

 subconically (8° in the anterior 0.39 and 25 in the aboral 

 0.17 total length). The pedicel is subcylindrical, with a 

 diameter near 0.3 oral diameter and with a length of 0.32 

 total length. At its aboral end is a slightly flaring skirt. 

 From the center of the skirt arises the conical (15 ), sharply 

 pointed lance, the length of which is 0.14 total length. 



The wall reaches a thickness of nearly 0.2 oral diameter at 

 the ledge, and is half as much just below; it thins down in 

 the lower bowl. There are very thin laminae and enclosed 

 radial secondary prisms in a single layer. In the ledge are 

 small, crowded alveoles in several rows. In the lance are 

 large hexagons in two layers. The surface has neat hex- 

 agonal structure, and there are 6 short pleats above the skirt. 

 The lumen does not enter the ledge, and in the lance it is 

 reduced to a canal. 



Length, 238 to 249IX. 



Xystonellopsis cyclas, like X. crassispinosa, has a thickened, 

 subcylindrical pedicel, but the lance is longer and more 

 slender, and the ledge more ringlike. It differs from X. 

 cymatica in having a thicker, more cylindrical pedicel and 

 thicker ledge. 



Recorded from three stations in the Pacific, as follows: 

 one (156) in the Pacific equatorial region, and two (158, 

 160) in the region of South Pacific island fields. 



There are 3 net samples, all taken at 100 meters. Fre- 

 quency, 4 per cent at stations 156, 160; average, 3.3 per cent. 



Temperature, 26?62-28?52 (27^65); salinity, 35.06-35.89 

 (35-54); density, 22.76-23.14 (22.93); P H » 8 -34- 8 -44 ( 8 -3 Q )- 



Xystonellopsis cymatica (Brandt) Jorgensen emended 

 Kofoid and Campbell 

 (Figure 65) 

 Xystonellopsis cymatica, Kofoid and Campbell, 1929, p. 245, 



fig. 458. 

 The relatively short lorica, with wide upper ledge, bare 



secondary ledge, conical bowl, thin pedicel, and short lance, 

 has a length of 4.82 oral diameters. The thin oral margin 

 is smooth. The bowl has a low upper cylindrical section 

 about 0.1 oral diameter in width, and the flat-edged, hori- 

 zontal ledge arises from its lower end. This upper ledge has 

 a diameter of 1.37 oral diameters, and its lower surface con- 

 tracts with concave contour to the bowl below. The lateral 

 wall within a length of 0.7 oral diameter is distinctly con- 

 cave. At the lower end arises a secondary ledge, with a 

 diameter of 1.25 oral diameters. Below this less distinct 

 ledge the bowl rapidly resumes its concave-conical form (20 

 in the upper 0.6 total length and 33 in the lower 0.4 total 

 length), with diameter at the aboral end, at the upper end 

 of the pedicel, only 0.16 oral diameter. The pedicel is narrow 

 and tubular, with a length of 0.37 total length, with some 

 slight skirtlike expansion at its distal end, and with little 

 lateral concavity in some individuals. From the lower end 

 of the skirt arises the narrow conical (7 ), pointed lance, 

 with a length of 0.58 oral diameter. 



The wall is thickest under the upper ledge, where it 

 reaches nearly 0.13 oral diameter; in the lower bowl it is 

 about three-tenths as much. There are thin, hyaline laminae 

 with enclosed radial secondary prisms in a single row, save 

 suborally, where there are several layers of small hexagons. 

 The lumen does not enter the ledges, but does follow the 

 outer contour of the skirt, and in the lance forms a narrow 

 canal. 



Length, 180 to 2581X. 



A part of the Carnegie loricae conform exactly to the 

 typical form, but a good many, like the figured specimen 

 (fig. 65), differ in two respects: (a) in the presence of a 

 secondary ledge, and (b) in the presence of a slight skirt 

 below a thinner pedicel. These differences are not, in our 

 opinion, sufficient to justify designating a new species, at 

 least with the material at hand. 



Xystonellopsis cymatica lacks the thick suboral angular 

 swelling of X. spicata, the more robust pedicel of X. cyclas 

 and X. crassispinosa, and the extremely narrow posterior 

 cone of X. mascarensis. In no case is the secondary ledge 

 like that of X. dicymatica. 



Recorded from twelve stations, five in the Atlantic and 

 seven in the Pacific, as follows: one (19) in the Sargasso 

 Sea, four (22, 23, 25, 27) in the Atlantic equatorial region, 

 one (41) in the Galapagos region, five (86, 92, 93, 96, 98) in 

 the region of South Pacific island fields, and one (no) in 

 the North Pacific trade region. 



There are 7 pump and 6 net samples, of which 2 were 

 taken at 50 meters and 11 at 100 meters. Frequency, 3 

 loricae in a pump sample at station no; average in pump 

 samples, 1.2 loricae. 



Temperature: Atlantic, net samples i4?6o-22?42 (i8?68); 

 Pacific, pump samples i4?55~27?65 (23?85). Salinity: 

 Atlantic, net samples 35.70-37.05 (36.15); Pacific, pump 

 samples 34.73-36.22 (35.52). Density: Atlantic, net samples 

 25.30-26.62 (25.98); Pacific, pump samples 22.75-26.11 

 (23.55). pH: Atlantic, net samples 7.93-8.25 (8.09); Pacific, 

 pump samples 7.92-8.28 (8.17). 



