84 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



Xystonellopsis gaussi (Laackmann) Kofoid and Campbell 



Xystonellopsis gaussi, Kofoid and Campbell, 1929, pp. 246-247, 

 fig. 480. 



The moderately elongated lorica, with armata-Vike form, 

 has a narrow lance and a length of 5.23 oral diameters. The 

 oral margin is thin and erect. The elongated bowl is sub- 

 conical (3° in the anterior 0.43 and 23° in the posterior 0.27 

 total length). The pedicel tapers (12°), has a length of 0.25 

 total length, and terminates in a squarely truncated, non- 

 expanded skirt. The lance is pencil-shaped (15°), and 0.5 

 oral diameter in length. 



The wall reaches 0.07 oral diameter in thickness in the 

 bowl, and has thin laminae which enclose faint, minute 

 alveoles. There are 8 right-wound (3°) discontinuous folds 

 on the pedicel. 



Length, 371 to 470I-I. 



Xystonellopsis gaussi has a pencil-like lance, rather than 

 a wide, conical lance as in X. armata. It differs from X. 

 acuminata in size, proportions, and presence of a distinct 

 pedicel; from both of these species it diflfers in having dis- 

 continuous folds rather than ridges on the pedicel. It has a 

 definite skirt, unlike X. heros and related species. 



Recorded from eight stations, two in the Atlantic and si.x 

 in the Pacific, as follows: two (2, 16) in the Gulf Stream, two 

 (35, 153) in the Pacific equatorial region, one (63) in the 

 South Pacific middle latitudes, one (75) in the Galapagos 

 region, and two (109, 151) in the North Pacific trade region. 



There are 4 pump and 9 net samples, of which i was 

 taken at the surface, 4 at 50 meters, and 8 at 100 meters. 

 Maximum frequency, 9 per cent at station 2; other records 

 above minimum (2 to 7 per cent) from stations 35, 63, 75, 

 151; averages, 4.2 per cent in Atlantic net samples, 4.0 per 

 cent and 3 loricae in Pacific net and pump samples, respec- 

 tively. 



Temperature: Atlantic, net samples 20?50-23?64 (2i?26); 

 Pacific, pump samples i5?84-22?73 (i8?84), net samples 

 i4?33-i9?8i (i7?22). Salinity: Atlantic, net samples 36.40- 

 36.43 (36.41); Pacific, pump samples 34.42-34.76 (34.62), 

 net samples 34.86-35.47 (35-03). Density: Atlantic, net 

 samples 24.84-25.76 (25.50); Pacific, pump samples 23.83- 

 25.48 (24.76), net samples 24.72-26.00 (25.48). pH: At- 

 lantic, net samples 8.16-8.23 (8.20); Pacific, pump samples 

 8.08-8.31 (8.15), net samples 7.88-8.18 (8.02). 



Xystonellopsis hastata (Biedermann) Kofoid and Campbell 

 (Figure 70) 



Xystonellopsis hastata, Kofoid and Campbell, 1929, p. 247, fig. 

 456. 



The fairly short lorica, with oral teeth, conical bowl, and 

 short pedicel and lance, has a length of 3.66 oral diameters. 

 The oral margin has 24 equidistant, short, triangular den- 

 ticles. The bowl expands slightly (1.13 oral diameters) 

 within 0.13 oral diameter, then contracts (3° in the anterior 

 1. 14 oral diameters and 34° in the posterior similar length); 

 the diameter at the lower end of the bowl is 0.3 oral diam- 

 eter, and the whole lorica is generally convex, with a suboral 

 ledge. The pedicel contracts from the lower end of the bowl 



(10°), has a length of i.o oral diameter, and at its lower 

 end has a short, expanded skirt. From the center of the 

 skirt arises the short (0.4 oral diameter), fairly stout, pointed 

 lance. 



The wall reaches o.i oral diameter in thickness across the 

 ledge where it is widest; it thins down to three-tenths as 

 much in the middle and lower bowl. There are thin laminae 

 with enclosed radial, secondary, rectangular prisms, with 

 minute alveoles within each one in several layers. The sur- 

 face has large hexagonal areas, except for the lance, which is 

 hyaline. There are 7 (8) short folds above the skirt on the 

 lower pedicel. The lower pedicel is yellowish, and denser 

 than the upper parts. 



Length, 244^1. 



Xystonellopsis hastata is unique in the genus in having 

 oral denticles. In general it is related to X. cymatica and 

 relatives of that species, but is longer and stouter, with fuller 

 lower bowl, relatively shorter pedicel, and less localized sub- 

 oral thickening. 



Recorded from five stations, three in the Atlantic and two 

 in the Pacific, as follows: three (23, 24, 25) in the Atlantic 

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

 region. 



There are 2 pump and 5 net samples, of which i was 

 taken at the surface and 6 at too meters. Maximum fre- 

 quency, 3 per cent at station 152; other records above mini- 

 mum (2 per cent) from stations 24, 35; average in Pacific 

 net samples, 1.2 per cent. 



Temperature: Atlantic,pump samples 15^55-27? 1 8(21 ?36), 

 net samples i4?6o-i5?55 (i5?07); Pacific, net samples 

 ii?48-i4?33 (i2?9o). Salinity: Atlantic, pump samples 

 35.22-35.61 (35.41), net samples 35.61-36.02 (35.83); Pacific, 

 net samples 34.73-34.91 (34.82). Density: Atlantic, pump 

 samples 22.84-26.34 (24.59), net samples 26.34-26.62 (26.44); 

 Pacific, net samples 26.06-26.50 (26.28). pH: Adantic, 

 pump samples 7.96-8.32 (8.14), net samples 7.93-8.18 (7.99); 

 Pacific, net samples 7.76-7.88 (7.82). 



Xystonellopsis heroica Kofoid and Campbell 



Xystonellopsis heroica Kofoid and Campbell, 1929, p. 247, fig. 

 473- 



The rather short lorica, of extreme slenderness and elon- 

 gation, has a length of 7.4 oral diameters. The oral margin 

 is thin. The bowl is swollen to a maximum of 1.17 oral 

 diameters within the upper oral diameter. Below this 

 swollen region it is subconical (4° in the anterior 0.37 and 

 30° in the posterior 0.21 total length). The pedicel-lance 

 has a length of almost 0.33 total length and is distally sharply 

 pointed. 



The wall scarcely reaches o.i oral diameter in thickness in 

 the thickened region and is elsewhere less than a third as 

 much. There are thin laminae with enclosed fine hexagons. 

 There are no lists or ridges and the whole lorica is glass- 

 clear. The lumen enters the pedicel as a canal. 



Length, 174 to 2i8|X. 



Xystonellopsis heroica has a bowl and pedicel-lance of 

 greater elongation than in X. pinnata and A", heros, which 



