36 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



subconical (42° in the flat-sided upper seven-tenths and 114° 

 in the lowermost rounded section). The aboral end is ob- 

 tusely rounded. 



The wall of the bowl has an irregular row of 10 closed, 

 subrectangular, large fenestrae and a pre-equatorial row of 

 large Syracosphaera. Minute circular areas (coccoliths.^) 

 cover the remainder of the surface. 



Length, 75^1. 



Dictyocysta nidulus resembles D. reticulata but differs 

 mainly in proportions, regularity of large fenestrae, presence 

 of large Coccolithophoridae, and general shape of bowl. 

 Dictyocysta mexicana has greater angularity, more projecting 

 aboral end, more localized fenestrae, and shorter length (57 

 to 66(^1). 



Recorded from one station (4) in the Atlantic drift, in a 

 net sample taken at 50 meters. Frequency, 6 per cent. 



Temperature, i4°32; salinity, 36.00; density, 26.91; pH, 

 8.15. 



Dictyocysta occidentalis Kofoid and Campbell 



Dictyocysta occidentalis Kofoid and Campbell, 1929, pp. 298- 

 299. fig- 556. 



The fairly small, symmetrical lorica, with wi/'/ra-like fenes- 

 tration, lepida-Vike collar, and globose bowl, has a length of 

 1.57 oral diameters. The oral margin is undulating, with 7 

 arches. The collar is subcylindrical, 0.63 of the length of the 

 bowl in length, with 7 subquadrangular, closed windows, 

 and thick beams and muUions. The bowl is globular, its 

 greatest diameter, at the middle, being 1.15 oral diameters. 

 There is a rounded shoulder just below the throat. The 

 aboral end is hemispherical. 



The wall of the bowl has an equatorial zone of 8 to 10 

 subequal, round fenestrae, a post-equatorial one of 6 to 8, 

 and an aboral group of very small ones. The meshwork is 

 heavy and pronouncedly minutely alveolar. Coccoliths are 

 often found, especially in the aboral fenestrae. 



Length, 55 to 62|.l. 



Dictyocysta occidentalis has a globose bowl somewhat like 

 that of D. polygonata, but the latter species has large circles 

 forming the wall of the bowl, and has no equatorial or other 

 limited zones of fenestrae. Dictyocysta duplex has "duplex" 

 walls and a very different collar. Dictyocysta tiara has 

 thinner beams and an ovoid bowl. 



Recorded from three stations in the Pacific, as follows: 

 one (136) in the California region and two (141, 144) in 

 the North Pacific middle latitudes. 



There are 3 pump samples, of which i was taken at the 

 surface and 2 at 50 meters. Frequency, minimum. 



Temperature, i8?69-25?3i (22?86); salinity, 34.64-35.38 

 (35.09); density, 23.46-24.84 (24.02); pH, 8.33-8.37 (8.34). 



Dictyocysta pacifica Kofoid and Campbell 

 Dictyocysta pacifica Kofoid and Campbell, 1929, p. 299, fig. 555. 

 The short lorica, with the general shape of mitra as well 

 as with similar fenestration, but with oral denticles, has a 

 length of 1.43 oral diameters. The oral margin is regularly 

 set with about 40 sparsely spaced, triangular denticles. The 

 collar is a segment of an inverted cone (10°) with a length 



of 0.57 total length, a diameter of 0.86 oral diameter at the 

 throat, and 6 squarish windows, each set into a relatively 

 wide frame. The windows are all closed, and the beams 

 and mullions are rather thick. The collar merges with the 

 plump bowl. The bowl expands from the throat to 1.14 

 oral diameters near its equator. Below this it is convex 

 conical (60° in the anterior part, increasing to 125° in the 

 lower half). The aboral end is pointed. 



The wall of the bowl has 2 rather regular and i irregular 

 row of fenestrae. The fenestrae of the first row, 10 in num- 

 ber, are similar in size to those of the second row, which 

 number 12; both sets are subcircular in shape and subequal 

 in size. The fenestrae of the distal set form an irregular 

 row of 6 small windows. The interfenestral area has smaller 

 polygons; coccoliths are not rare in this distal region. 



Length, 41 to 52^1. 



Dictyocysta pacifica differs from the species of the mitra 

 type in having oral denticles; D. extensa and D. spinosa, 

 however, have larger spinelike teeth instead of tiny spikes. 

 In some ways D. pacifica recalls D. minor, but it has smaller 

 fenestrae in the distal group, as well as oral denticles. 



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

 (35, 35-36) in the Pacific equatorial region, one (45) in the 

 CJalapagos region, and one (136) in the California region. 



There are 3 net samples and i pump sample, of which i 

 was taken at the surface, i at 50 meters, and 2 at 100 meters. 

 Frequency, 2 per cent at station 136; other records minimum. 



Temperature: pump sample i8?87, net samples 16^30- 

 2i?69 (i8?99). Salinity: pump sample 35.02, net samples 

 34.88-35.21 (35.04). Density: pump sample 25.09, net 

 samples 24.48-25.60 (25.04). pH: pump sample 8.39, net 

 samples 7.92-8.12 (8.02). 



Dictyocysta reticulata Kofoid and Campbell 



Dictyocysta reticulata Kofoid and Campbell, 1929, p. 300, fig. 



560; Marshall, 1931, pp. 653-654. 

 Dictyocysta lepida, Hofker, 1931, pp. 382-384, figs. 76-78. 



The plump lorica, with arched collar windows in a single 

 row resembling the columns of a Greek temple, wide, low 

 bowl, rounded aboral end, and large oval fenestrae in the 

 bowl, has a length of 1.37 oral diameters. The oral margin 

 has 6 (7) flattened arches. The collar is nearly cylindrical, 

 0.46 total length in length, and there are 6 (7) tall, subequal 

 windows. The subhemispherical bowl reaches 1.15 oral 

 diameters at 0.5 total length, and thence more or less evenly 

 rounds to the unmodified aboral end. 



The wall of the bowl is hardly 0.03 oral diameter in 

 thickness. The whole bowl is fenestrated with subuniform, 

 rounded, deeply pitted polygons except for a single row of 

 large subequal, closed, oval fenestrae, 6 (7) in number, which 

 are in the bowl's equatorial region. The beams and mullions 

 of the closed fenestrae of the collar are hyaline, rounded, and 

 squarish in form. 



Length, 55 to 65(^1. 



Hofker's material probably includes several related species, 

 as this writer does not closely differentiate the species of this 

 group. 



