OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



lana, from the coast of China. Kofoid and Campbell (1929) 

 placed Dictyocysta among the more complex Tintinnoina, 

 between the Undellidae and Tintinnidae, only to insure its 

 isolation from Codonelhi, to which it had previously been 

 allied. 



Dictyocysta is found abundantly in the tropics, although 

 some species are northern in distribution in the Atlantic. 

 None is antarctic. 



Seventeen species are described here. 



Dictyocysta dilatata Brandt 

 Dictyocysta dilatata, Kofoid and Campbell, 1929, p. 288, fig. 549. 



The regular, fairly large lorica, with mitra-\)ke. fenestra- 

 tion, distinct set-ofif collar, and pointed aboral end, has a 

 length of 1.4 oral diameters. The oral rim has 8 flattened 

 arches and is decidedly undulating. The collar is inverted 

 subconical, flaring (22°); its length is 0.23 total length; its 

 diameter at the lower end is 0.89 oral diameter; and it has 8 

 rounded, subequal, rectangular windows with heavy beams 

 and mullions. The bowl is acorn-like, without shoulder, and 

 reaches a maximum diameter of i.o oral diameter at 0.58 

 total length from the oral rim. The aboral region is convex 

 conical (62°), and the aboral end is pointed. 



The wall of the bowl has a maximum of 7 vertical rows 

 of unequal, squarish to rounded, rarely subpentagonal 

 fenestrae. These fenestrae number 12, 12, 16, 8, 6, and 5 

 respectively in horizontal rows. The smaller ones are mostly 

 in the aboral 3 rows. The framework which encloses the 

 windows is thick and heavy. All windows are closed by 

 hyaline panes. 



Length, 58 to jo\l. 



Dictyocysta dilatata is of the general D. mitra type. It 

 differs from mitra in the shape of the collar, pointed aboral 

 end, and trimmer form. Dictyocysta obtusa lacks clear dis- 

 tinction between collar and bowl, as does also D. jenestrata; 

 and D. spinosa, though of similar type, has oral spinules. On 

 the whole, dilatata is a clear-cut, easy species to recognize. 



Recorded from ten stations in the Pacific, as follows: four 

 (54, 62-63, 64, 65) in the South Pacific middle latitudes, one 

 (68) in the Galapagos region, one (no) in the North Pacific 

 trade region, two (131, 148) in the California region, and 

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



There are 4 pump and 8 net samples, of which 3 were 

 taken at the surface and 9 at 100 meters. Maximum fre- 

 quency, 12 per cent at station 131; other records above mini- 

 mum from stations 54, 65, 68, 145; average in net samples. 

 4.3 per cent. 



Temperature: pump samples i6?58-20?io (i7?88), net 

 samples I2?i2-20?6i (i7?62). Salinity: pump samples 

 34-47-34-95 (34-70. net samples 34.30-35-35 (34-56)- Den- 

 sity: pump samples 24.72-25.15 (24.96), net samples 24.33- 

 25.52 (25.00). pH: pump samples 8.14-8.31 (8.24), net 

 samples 8.10-8.32 (8.15). 



Dictyocysta duplex Brandt emended Kofoid and Campbell 

 Dictyocysta duplex, Kofoid and Campbell, 1929, p. 289, fig. 564. 



The large lorica, with collar resembling a colonnade of a 

 Greek temple, globose bowl, and "duplex" fenestration, has 



a length of 1.56 oral diameters. The oral rim is smooth, and 

 lacks the arches characteristic of many other species. The 

 collar is 0.75 oral diameter in length, cylindrical, and formed 

 by 7 tall, rectangular, subequal windows with rounded edges 

 (height of windows is 1.2 their width) and with hyaline, 

 rodlike beams and mullions. All the windows are open. The 

 bowl is globular, with its maximum diameter of 1.22 oral 

 diameters near its middle. There is no distinct shoulder, the 

 bowl simply rounding from the neck to its widest level. The 

 aboral end is hemispherical. 



The wall of the bowl is made up of large doubled or 

 "duplex" overlapping circles with hyaline areas enclosed. 

 Overlapping areas commonly include smaller circles. The 

 circles are the sites of coccoliths. 



Length, 60 to 751^1. 



Dictyocysta duplex bears some similarity to D. polygonata, 

 but the duplex wall and collar are different. None of the 

 other species has similar walls, and, indeed, this character 

 is shared only by isolated examples in other genera, espe- 

 cially Codonella and Codonaria. 



Recorded from four stations, one in the Atlantic and three 

 in the Pacific, as follows: one (23) in the Atlantic equa- 

 torial region, one (48) in the region of South Pacific island 

 fields, one (100) in the North Pacific trade region, and one 

 (148) in the California region. 



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

 taken at the surface and i each at 50 and 100 meters. Maxi- 

 mum frequency, 3 per cent at station 148; other records 2 

 per cent. 



Temperature: Atlantic, net sample 20^90; Pacific, pump 

 samples 20?ia-27?73 (23?9i), net sample 23?63. Salinity: 

 Atlantic, net sample 36.04; Pacific, pump samples 34.72-34.95 

 (34.83), net sample 36.44. Density: Atlantic, net sample 

 25.30; Pacific, pump samples 22.29-24.72 (23.50), net sample 

 24.86. pH: Adantic, net sample 8.14; Pacific, pump sample 

 8.21, net sample 8.23. 



Dictyocysta elegans Ehrenberg emended Kofoid 

 and Campbell 



Dictyocysta elegans, Kofoid and Campbell, 1929, pp. 289-290, 

 fig. 570. 



The moderately large lorica, with double row of windows, 

 acorn-like bowl with 3 rows of fenestrae, and rounded aboral 

 end, has a length of 1.46 oral diameters. The undulating 

 oral margin has a thin vertical list and 8 flattened arches. 

 The collar is cylindrical, with a length of 0.5 total length, 

 and with the diameter at the lower end equal to that of the 

 oral margin. The upper half of the collar has 8 inverted 

 pentagonal windows, and the lower part has 10 smaller, 

 squarish to pentagonal ones. The beams and mullions are 

 heavy and rounded, and the windows are all open. The 

 bowl is shaped like an acorn cup with traces of shoulder 

 (i.i oral diameters in diameter) a little below the lower 

 limit of the collar, and thence it rapidly contracts (53° in 

 the flat-sided upper two-thirds, and 8q° lower down). The 

 aboral end is rounded. 



The bowl has 3 rows of major, closed fenestrae; one of 

 these rows, of 10 subequal, rounded fenestrae, is near the 



