94 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



quency, 2 per cent at station 27; other records minimum; 

 average in Atlantic net samples, 1.3 per cent. 



Temperature: Atlantic, net samples i8?o8-26?79 (23?56); 

 Pacific, pump sample 23?25. Salinity: Atlantic, net samples 

 36.03-36.63 (36.30); Pacific, pump sample 34.60. Density: 

 Atlantic, net samples 23.79-26.06 (24.73); Pacific, pump 

 sample 23.58. pH: Atlantic, net samples 8.09-8.30 (8.21); 

 Pacific, pump sample 8.22. 



Xystonella treforti (Daday) Laackmann 



(Figure 68) 



Xystonella treforti, Kofoid and Campbell, 1929, p. 238, fig. 452; 



Marshall, 1934, p. 651. 

 Histonella treforti, Hofker, 1931, p. 381. 



The elongated, chalice-shaped lorica, with swollen skirt 

 and lance, has a length of 4.9 oral diameters. The thin oral 

 cuff is erect. The suboral trough surrounds the cuff, and its 

 diameter at the outer edge is 1.38 oral diameters; the trough 

 is deeply concave. The bowl flares (35°) within the anterior 

 0.45 oral diameter, the diameter at the lower end of the flare 

 being 1.13 oral diameters. The bowl contracts steadily below 

 this level within a cone (10°) with a length of 0.3 total 

 length, then becomes steeper (22°) for 0.38 total length, and 

 again below becomes narrower (5°) for i.o oral diameter. 

 At the lower end is the skirt. This is swollen and knoblike, 

 and has 4 to 8 downward-directed prongs. The short lance 

 (0.31 oral diameter) is a pointed peg. 



The wall is thickest below the suboral trough, where it 

 reaches 0.17 oral diameter; it gradually thins so that just 

 above the skirt it is only a third as much, or less. There are 

 thin laminae which enclose subequal, rectangular, radial 

 secondary prisms. Within these are minute primary alveoles. 

 The surface is covered with a uniform hexagonal mesh. The 

 oral cuff is hyaline, as is the lance. The skirt is denser than 

 the rest of the bowl, and of a dirty brown hue. The lumen 

 enters the lance as a cylindrical canal. 



Length, 2y6\i. 



The loricae of this expedition do not have so long a bowl 

 as that figured by Kofoid and Campbell, but they differ from 

 X. minuscula in this regard. Marshall's (1934) loricae are 

 much longer (405 to 4691^1) than any of the Carnegie speci- 

 mens. 



Xystonella treforti has a longer, less directly conical bowl 

 than X. minuscula. It lacks the spiral shelf of X. scandens, 

 and none of the remaining species have skirts. 



Recorded from fifty-seven stations, twenty in the Atlantic 

 and thirty-seven in the Pacific, as follows: four (2, 14, 15, 16) 

 in the Gulf Stream, five (17, 18, 19, 20, 21) in the Sargasso 

 Sea, eight (22, 23, 24, 25, 26, 27, 29, 30) in the Atlantic 

 equatorial region, three (31, 32, 34) in the Caribbean Sea, 

 three (35, 35-36, 36) in the Pacific equatorial region, twelve 

 (40, 41, 42, 43, 45, 46, 68, 69, 70, 71, 73, 77) in the Galapagos 

 region, two (48, 49) in the region of South Pacific island 

 fields, six (54, 55, 63, 64, 65, 67) in the South Pacific middle 

 latitudes, four (132, 135, 137, 146) in the California region, 

 five (138, 139, 140, 150, 151) in the North Pacific trade 

 region, and five (112, 113, 143, 144, 145) in the North Pacific 



middle latitudes. Xystonella treforti is one of the more 

 widely distributed species of the warmer regions of the 

 ocean, and avoids the cold areas. 



There are 33 pump and 57 net samples, of which 20 were 

 taken at the surface, 29 at 50 meters, and 41 at 100 meters. 

 The increase with depth in this instance is possibly signifi- 

 cant. Maximum frequency, 52 per cent between stations 35 

 and 36; other records above minimum (2 to 44 per cent) 

 from stations 2, 14, 15, 16, 17, 19, 20, 22, 23, 24, 27, 32, 34, 

 35' 40, 41. 42. 45' 46. 48, 54- 63, 65, 69, 71, 77, 112, 113, 135, 

 145, 150; average in net samples in both Atlantic and Pacific, 

 8.1 per cent; in Atlantic pump samples, 3.3 loricae. | 



Temperature: Atlantic, pump samples i4?02-26?98(23?32), 

 net samples i4?6o-25?56 (2i?97); Pacific, i3?93-26?9i 

 (i8?94) and i4?33-26?05 (i9?3i), respectively. Salinity: 

 Adantic, pump samples 35.10-37.00 (36.25), net samples 

 35-59-37-I5 (36-33); Pacific, 33.40-36.06 (34.93) and 34.30- 

 36.44 (34.94), respectively. Density: Adantic, pump samples 

 23.84-26.66 (24.72), net samples 24.25-26.66 (25.37); Pacific, 

 22.72-26.21 (24.23) and 22.89-26.17 (24.92), respectively. 

 pH: Adantic, pump samples 8.06-8.37 (8-23), net samples 

 7-93-8-37 (7-97); Pacific, 7.68-8.47 (8.17) and 7.87-8.34 

 (8.08), respectively. 



UNDELLIDAE Kofoid and Campbell 



Undellidae Kofoid and Campbell, 1929, p. 251. 



The Undellidae include Undella, Amplectella, Amplec- 

 tellopsis, Cricundella, Proplectella, and Undellopsis, six 

 genera in all. All are present in the material of this expedi- 

 tion. Most of the genera are characteristic of warm water 

 but are not limited to that region of the ocean; none is 

 antarctic. 



Undellinae, new subfamily 



The Undellinae include those genera of the Undellidae in 

 which there is no suboral ledge and no inner collar, namely, 

 Undella, Amplectella, Amplectellopsis, and Cricundella. u 



UNDELLA Daday emended I 



Undella, Kofoid and Campbell, 1929, p. 258. 



Undella is better known than the genera which have been 

 more recently established; in most instances more advanced 

 species were formerly assigned to Undella. As a whole the 

 members of Undella are simple, thimble-shaped forms with 

 very little ornamentation or special elaboration in structure. 

 The species are rather difficult to distinguish and sometimes 

 intergrade. 



Nearly all species of Undella occur in warm seas, and there 

 seems to be little geographical limitation within the tropics. 



Fifteen species are described here, of which two imusually 

 interesting ones are new. 



Undella attenuata Jorgensen emended Kofoid and Campbell 



Unihlla attenuata, Kofoid and Campbell, 1929, p. 2fio, fig. 510. 



The moderately elongated lorica, of general hyalma form, 

 with biconical aboral region, has a length of 3.1 oral diam- 

 eters. The oral margin is the thin, erect inner lamina. The 



