TAXONOMY AND DISTRIBUTION 



85 



species it otherwise rather closely resembles. Were it lack 

 ing in suboral thickening, it would be close to Parundella 

 longa. 



Recorded from one station (94) in the region of South 

 Pacific island fields, in a pump sample taken at 100 meters. 

 Frequency, minimum. 



Temperature, 28?66; salinity, 3547; density. 22.56; pH, 

 8.21. 



Xystonellopsis heros (Cleve) Kofoid and Campbell 



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

 484. 



The very tall lorica, with distinct division between pedicel 

 and lance, has a length of 7.9 oral diameters. The oral rim 

 is flattened. The long bowl tapers (5 ) directly from the 

 nm without local modification throughout its whole length, 

 and reaches 0.3 oral diameter at the squarely truncated aboral 

 end, which is the homologue of the skirt of other species. 

 The lance is narrow conical (2 ), 0.58 oral diameter in 

 length, and sharp-pointed at the free tip. 



The wall has a subuniform thickness of 0.08 oral diam- 

 eter, has thin laminae with enclosed faint hexagons, and the 

 surface is glass-clear save for a few irregular, discontinuous, 

 subvertical lines down the lower three-tenths. The lumen 

 enters the lance as a canal. 

 Length, 475^. 



Xystonellopsis heros is elongated like X. lyammeri, but 

 has no skirt. Xystonellopsis acuminata has a plumper bowl 

 with distinct pedicel region, as do X. gaussi, X. lenuirostrts, 

 and X. armata. 



Xystonellopsis heros, as here described, hardly resembles 

 the figure given by Brandt (1906), differing in length, ab- 

 sence of folds on the bowl, and thinner lance. It is probably 

 the same as the species designated by Kofoid and Campbell 

 (1939) as X. tropica, new species. If so, the distributional 

 data in this report include records of both species. 



Recorded from twenty-one stations, twelve in the Atlantic 

 and nine in the Pacific, as follows: two ( 14, 16) in the Gulf 

 Stream, two (17, 18) in the Sargasso Sea, five (24, 25, 27, 

 28, 29) in the Atlantic equatorial region, three (31, 33, 34) 

 in the Caribbean Sea, one (75) in the Galapagos region, 

 three (109, 139, 151) in the North Pacific trade region, one 

 (113) in the North Pacific middle latitudes, two (136, 147) 

 in the California region, and two (152, 153) in the Pacific 

 equatorial region. 



There are 7 pump and 21 net samples, of which 7 were 

 taken at 50 meters and 21 at 100 meters. Maximum fre- 

 quency, 34 per cent at station 151; other records above mini- 

 mum (2 to 19 per cent) from stations 14, 16, 27, 29, 31, 33, 

 34, 75, 136, 147, 152, 153; averages in net samples, 1.5 and 

 1 1.3 per cent in the Atlantic and Pacific, respectively. 



Temperature: Atlantic, pumpsamples i8?o8-23?64 (22^44), 

 net samples i4?6o-26?04 (>o?63); Pacific, i9?8i-23?77 

 (22^02) and i4?32-22?73 (i8?64), respectively. Salinity: 

 Atlantic, pump samples 36.03-36.48 (36.30), net samples 

 35.59-36.82 (36.32); Pacific, 34.59-35.18 (34.82) and 34.42- 

 35.47 (34.86), respectively. Density: Atlantic, pump samples 



24.84-26.06 (25.6$), net samples 23.98-26.66 (25.56); Pacific, 

 23.42-24.72 (24.08) and 23.83-25.75 (25.01), respectively. 

 pH: Atlantic, pump samples 8.09-8.23 (8.18), net samples 

 7.93-8.27 (8.16); Pacific, 8.18-8.28 (8.23) and 7.87-8.39 

 (8.18), respectively. 



Xystonellopsis inaequalis Kofoid and Campbell 



Xystonellopsis inaequalis Kofoid and Campbell, 1929, pp. 247- 



248, fig. 466. 

 Xystonellopsis dicymatica, Kofoid and Campbell, 1929, rifj. 467 



(for p. 245 see X. dicymatica). 



The fairly short lorica, of general dicymatica type, with 

 the lower ledge much wider than the upper one, has a length 

 of 7.0 oral diameters. The thin oral margin is erect. The 

 bowl forms a short cylinder within the anterior 0.25 oral 

 diameter, at the lower end of which arises the Hat, ringlikc 

 upper ledge, with a diameter of 1.28 oral diameters. Below 

 this ledge the suboral band swells with a wide sigmoid curve 

 to the secondary or lower ledge, the diameter of which is 

 1.68 oral diameters. The suboral band occupies the anterior 

 1.08 oral diameters. The bowl below the band is subcorneal 

 (14 increasing to 30 in the lower oral diameter). The 

 pedicel tapers (2 ), with a length of 0.39 total length, and 

 at its distal end is an expanded skirt. The free edge of this 

 skirt has 6(8) clawlike projections. From the center of the 

 skirt arises the pencil-like lance (0.64 oral diameter in 

 length). 



The wall is thickest in the suboral band, where it reaches 

 as much as 0.2 oral diameter; elsewhere it is quickly reduced 

 to three-tenths as much or even less. There are thin, hyaline 

 laminae with enclosed radial secondary prisms in a single 

 layer, save in the band, where there are several layers of 

 smaller hexagons. The lumen does not enter the ledges. 

 The whole lorica, save the skirted region, is translucent; the 

 latter is brownish. 

 Length, 246 to 350ft. 



The Carnegie loricae are more slender (7.0 oral diam- 

 eters as against 5.75) than usual; they are also longer (up to 

 35011). Most of them have a concave secondary ledge, this 

 being like a dish or saucer rather than a flat ring. 



Xystonellopsis inaequalis resembles X. dicymatica closely 

 except that the lower ledge is much wider and the suboral 

 band is generally wider. Intergrades do not seem to be 

 frequent. 



Recorded from eight stations, four each in the Atlantic 

 and the Pacific, as follows: three (18, 19, 20) in the Sargasso 

 Sea, one (34) in the Caribbean Sea, two (35, 37) in the 

 Pacific equatorial region, one (78) in the Galapagos region, 

 and one (82) in the region of South Pacific island fields. 



There are 3 pump and 5 net samples, of which 3 were 

 taken at 50 meters and 5 at 100 meters. Frequency, 3 per 

 cent at station 19; 2 per cent at station 35; average in Atlantic 

 net samples, 1.2 per cent. 



Temperature: Atlantic, net samples 20?32-24?63 (22?48); 

 Pacific, net sample i6?3o, pump samples i9?82-24?34 

 (22?o6). Salinity: Atlantic, net samples 36.55-37.05 (36.78); 

 Pacific, net sample 34.88, pump samples 34.53-36.46 (35.76). 



