TAXONOMY AND DISTRIBUTION 



8l 



Pacific, pump samples i6?90-28?05 (2i?36), net samples 

 i4?33-2i?69 (i8?27). Salinity: Atlantic, net samples 36.00- 

 36.04 (36.02); Pacific, pump samples 34.40-35.02 (34.74), 

 net samples 34.30-35.21 (34.79). Density: Atlantic, net sam- 

 ples 24.67-25.30 (24.98); Pacific, pump samples 21.95-25.26 

 (24.56), net samples 24.24-26.06 (25.04). pH: Atlantic, net 

 samples 8. 14-8. 18 (8.15); Pacific, pump samples 8.12-8.39 

 (8.30), net samples 7.88-8.38 (8.18). 



Xystonellopsis brandti (Laackmann) [orgensen 



Xystonellopsis brandti, Kofoid and Campbell, 1929, p. 241, fig. 

 474- 



The rather short lorica, of extreme narrowness, with sub- 

 oral swelling and conical pedicel with merged lance, has a 

 length of 7.8 oral diameters. The oral margin is thin and 

 erect. The bowl swells in a zone of the uppermost oral 

 diameter to 1.3 oral diameters at 0.3 oral diameter below the 

 rim. The upper part of this swollen region has a rounded 

 shoulder, and the lower part tapers (23°) and merges with 

 the bowl below. The bowl below the swollen region swells 

 to I.I oral diameters at 2.8 oral diameters below the rim, 

 and then is conical (12°) for the remainder of the length of 

 the lorica. The pedicel-lance occupies about 1.5 oral diam- 

 eters, and the distal tip is sharp. 



The wall has a thickness of nearly 0.2 oral diameter across 

 the widest part of the bowl, but in the lower bowl is only 

 0.05 or less. There are thin laminae with faint, fine hexa- 

 gons in several layers, especially suborally. The lorica is 

 hyaline, save that the pedicel-lance is dense. There are 6 

 low, winglike fins which continue from the lower bowl to 

 the lower pedicel. The lumen is reduced to a canal in the 

 lance, and does not enter the suboral thickening. 



Length, 196 to 2251.1. 



In many respects Xystonellopsis brandti is unique, but it 

 is possibly somewhat like X. constricta. It is, however, 

 shorter, lacks the tubular, constricted lower bowl, and has 

 more suboral thickening. 



Recorded from two stations, one each in the Atlantic and 

 the Pacific, as follows: one (ig) in the Sargasso Sea, and one 

 (80) in the Galapagos region. 



There are i pump and i net sample, both taken at 50 

 meters. Frequency, minimum. 



Temperature: Atlantic, net sample 25?3i; Pacific, pump 

 sample 26V06. Salinity: Atlantic, net sample 37.15; Pacific, 

 pump sample 35.95. Density: Atlantic, net sample 24.89; 

 Pacific, pump sample 23.75. pH: Atlantic, net sample 8.27: 

 Pacific, pump sample 8.19. 



Xystonellopsis conicacauda Kofoid and Campbell 

 Xystonellopsis conicacauda Kofoid and Campbell, 1929, p. 243, 



fig- 465- 

 The fairly short lorica, with duplicated skirts and short, 

 conical lance, has a length of 5.7 oral diameters. The oral 

 margin is thin and erect. The bowl swells rapidly to a 

 diameter of 1.93 oral diameters within the anterior o.i oral 

 diameter, forming a thickened ledge. The lower part of the 

 swollen region extends for the anterior 0.25 total length, 



gradually being reduced posteriorly. Below this region the 

 bowl becomes subconical (10°) for the remainder of its 

 length. At the lower end it swells to form the upper, e.x- 

 panded skirt. Below this skirt is a short cylindrical section 

 (approximately i oral diameter in length) with a slight skirt 

 at its lower end. From the center of this skirt arises the 

 lance, which is conical (60°), with its length less than its 

 basal diameter. 



The wall has a thickness of 0.28 oral diameter across the 

 ledge. The lumen does not enter the ledge, but does follow 

 the external contour of the lance. The wall is otherwise like 

 that of X. paradoxa. 



Length, 188 to 2291.1. 



Xystonellopsis conicacauda resembles X. paradoxa, but its 

 lance is shorter, wider, and more conical; the bowl is pro- 

 portionately longer. 



Recorded from one station (19) in the Sargasso Sea, in a 

 net sample taken at 100 meters. Frequency, minimum. 



Temperature, 22?42; salinity, 37.05; density, 25.67; pH, 

 8.25. 



Xystonellopsis crassispinosa Kofoid and Campbell 

 (Figure 64) 

 Xystonellopsis crassispinosa Kofoid and Campbell, 1929, p. 244, 

 fig. 460. 



The fairly short lorica, of general cymatica type but with 

 thick pedicel and stout lance, has a length of 4.7 oral diam- 

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

 immediately below the rim to form a rounded, thick ledge 

 with a diameter of 1.28 oral diameters; the ledge has a width 

 of 0.32 oral diameter. The bowl below the ledge is sub- 

 conical (8° increasing to 33° in the aboral 0.76 oral diam- 

 eter). The pedicel is thick (0.25 oral diameter) and tubular, 

 with a length of 0.32 total length, and with a slightly ex- 

 panded skirt at its distal end. The skirt has 8 (12) clawlike 

 points, and above each is a short pleat which reaches the 

 lower end of the pedicel. The lance arises from the center 

 of the skirt, has a length of 0.6 oral diameter, and is stout, 

 conical ( 16°), and distally blunted. 



The wall is thickest suborally, where it reaches nearly 0.09 

 oral diameter; it tapers to less than three-tenths as much in 

 the lower bowl. There are thin laminae, which enclose 

 radial, secondary rectangles, save in the ledge, where there 

 are several layers of small hexagons. The lumen does not 

 enter the ledge. 



Length, 244 to 265^. 



Xystonellopsis crassispinosa differs from X. cymatica and 

 related species in the stoutness of the pedicel and lance, and 

 from X. spicata in the narrower ledge. 



Recorded from ten stations, three in the Atlantic and 

 seven in the Pacific, as follows: one (18) in the Sargasso Sea, 

 two (22, 23) in the Atlantic equatorial region, two (41, 45) 

 in the Galapagos region, one (95) in the region of South 

 Pacific island fields, two (136, 146) in the California region, 

 one (145) in the North Pacific middle latitudes, and one 

 (150) in the North Pacific trade region. 



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

 taken at 50 meters and 9 at 100 meters. Maximum frequency. 



