TAXONOMY AND DISTRIBUTION 



87 



The Carnegie loricae are longer and also less full aborally 

 than those from other sources. 



Xystonellopsis ornata can scarcely be confused with any 

 other Xystonellopsis, for none of them has the upper spool- 

 like structure, nor the aboral dagger-shaped mass. This 

 upper differentiation is possibly correlated with the relation 

 of the lorica to the water, and the lower mass may act as a 

 counterpoise in directed locomotion. 



Recorded from three stations in the Pacific, as follows: 

 one (35) in the Pacific equatorial region, and two (41, 74) 

 in the Galapagos region. 



There are 3 net samples, of which 1 was taken at 50 

 meters and 2 at 100 meters. Frequency, 6 per cent at station 

 41; average, 3.3 per cent. 



Temperature, i4?55-i6?55 (i5?79); salinity, 34.88-35.14 

 (35.01); density, 25.60-26.11 (25.82); pH, 7.89-7.92 (7.91). 



Xystonellopsis paradoxa (Cleve) Jorgensen 

 (Figure 63) 

 Xystonellopsis paradoxa, Kofoid and Campbell, 1929, p. 249, 

 fig- 463- 



The fairly short lorica, with duplicated knob and slender 

 lance, has a length of 4.0 oral diameters. The oral margin is 

 sharp-edged and erect. The bowl expands (40 ) within the 

 anterior 0.35 oral diameter to a diameter of 1.23 oral diam- 

 eters, at that level forming a ledge. Below, the bowl con- 

 tracts, and then swells to 1.12 oral diameters at 0.58 oral 

 diameter below the rim. The swollen region continues over 

 a band of approximately 0.5 oral diameter, and then con- 

 tracts subconically (n°) for a length equal to 1.62 oral 

 diameters, below which it rapidly contracts (6o c ) for a 

 short distance. The pedicel begins flaring (75°), and reaches 

 0.77 oral diameter at 0.71 total length from the rim. The 

 lower edge of this skirt is crenulate, and left-turning, short 

 folds extend upward from the crinkles. The secondary skirt 

 arises at 0.5 oral diameter below the primary one. Its width 

 is similar to its length, and, like the former one, its edge is 

 crenulated. The lance (0.73 oral diameter in length) is nar- 

 row conical (9°), arises from a spreading base, and is pointed 

 at its free tip. 



The wall is thickest in the suboral swollen region, where 

 it reaches 0.16 oral diameter; elsewhere it is only a tenth as 

 much. There are thin laminae which enclose radial second- 

 ary prisms. The lumen is generally conical in the bowl, 

 but in the skirted region it narrows down, and finally forms, 

 in the lance, a sinuous canal. The surface shows hexagonal 

 prisms, save for the hyaline lance. 



Length, 231(1. 



Xystonellopsis paradoxa resembles X. conicacauda closely, 

 save that the lance is longer and much more slender. The 

 region between the two skirts, also, is much narrower in 

 paradoxa. In some ways its resemblance to X. dilatata is 

 apparent, save as the latter lacks the thick suboral region and 

 the two skirts, and has a shorter, wider lance like that of 

 cpnicacauda. 



Recorded from eight stations, three in the Atlantic and five 

 in the Pacific, as follows: two ( 19, 20) in the Sargasso Sea, one 



(23) in the Atlantic equatorial region, two (41, 75) in the 

 Galapagos region, one (63) in the South Pacific middle lati- 

 tudes, and two (101, no) in the North Pacific trade region. 



There are 4 pump and 5 net samples, of which 1 was 

 taken at 50 meters and 8 at 100 meters. Frequency, 2 per 

 cent at station 20; other records minimum. 



Temperature: Atlantic, net samples 20?99-22?56 (2i?99); 

 Pacific, net sample i8?40, pump samples ^55-25? 12 

 (i8?36). Salinity: Atlantic, net samples 56.02-37.73 (36.71); 

 Pacific, net sample 35.47, pump samples 34.58-35.02 (34.85). 

 Density: Atlantic, net samples 25.30-25.67 (25.45); Pacific, 

 net sample 25.55, pump samples 23.40-2(1.1 1 (25.00). pll: 

 Atlantic, net samples 8.14-8.25 (8.19); Pacific, net sample 

 8.10, pump samples 7.92-8.23 (8.09). 



Xystonellopsis pulchra (Kofoid) Kofoid and Campbell 

 (Figure 66) 



Xystonellopsis pulchra, Kofoid and Campbell, 1929, p. 250, fig. 



471. 

 The rather elongated lorica, with three ledges, thick 

 pedicel, skirt, and short lance, has a length of 7.0 oral diam- 

 eters. The oral margin is thin and erect. The bowl forms 

 a short cylinder with a width of less than 0.1 oral diameter, 

 and from its lower edge arises the thin upper ledge, with a 

 diameter of 1.55 oral diameters. Below this ledge arise two 

 others; the first of these, with a diameter of 1.61 oral diam- 

 eters, and the second, with a diameter of 1.67 oral diameters, 

 are at 0.9 and 1.42 oral diameters below the oral rim. All 

 these ledges are biconvex, the lower two being thicker than 

 the upper one. The region of the bowl occupied by them is 

 wider and thicker than below. The lower bowl is generally 

 conical (18 in the upper half and 33 in the lower section). 

 The diameter of the bowl at the distal end is 0.42 oral diam- 

 eter. The pedicel is tubular, and nearly 0.44 total length in 

 length, with a lower, somewhat expanded, skirtlike distal 

 end; this region is pleated with about 12 low, vertical folds. 

 From the center of this structure arises the pencil-like lance 

 (0.61 oral diameter in length), with blunted tip. 



The wall is thickest (less than 0.08 oral diameter) in the 

 upper bowl, and thins to two-thirds as much lower down. 

 There are thin laminae which enclose a single layer of radial 

 secondary prisms; these, in turn, include several layers of 

 alveoles. In the ledges there are several layers of hexagons. 

 The lumen conforms to the outer contour except suborally. 

 Length, 360(1. 



Xystonellopsis pulchra resembles X. abbreviata, but has a 

 wider suboral band, longer pedicel, and stouter proportions. 

 It lacks the distal twisted lines of X. torta and the repeated 

 skirts of X. laticincta, and has more rings than X. dicymatica. 

 Recorded from seventeen stations, three in the Atlantic 

 and fourteen in the Pacific, as follows: three (23, 25, 29) in 

 the Atlantic equatorial region, two (35, 152) in the Pacific 

 equatorial region, five (41, 42, 44, 45, 68) in the Galapagos 

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

 three (132, 136, 146) in the California region, one (144) in 

 the North Pacific middle latitudes, and one (151) in the 

 North Pacific trade region. 



