TAXONOMY AND DISTRIBUTION 



93 



Recorded from one station (14) in the Gulf Stream, in a 

 net sample taken at 100 meters. Frequency, minimum. 



Temperature, I4?02; salinity, 35.59; density, 26.66; pH, 

 8.06. 



Type locality, station 14, at 100 meters; latitude 42° 10' 

 north, longitude 47° 19' west. 



Xystonella lanceolata (Brandt) Brandt 



XystoncUa hiiiceolata, Kofoid and Campbell, 1929, p. 236, fig. 

 449- 



The rather short, conical lorica, with thick, conical horn of 

 moderate length, has a length of 5.35 oral diameters. The 

 oral rim is low, and hidden by the higher sides of the outer 

 edge of the outer wall of the suboral trough; the trough is 

 concave, and the diameter of its outer edge is 1.28 oral diam- 

 eters. The bowl flares (34°) within the upper 0.35 oral 

 diameter, and the diameter at the lower end of the flare is 

 I.I oral diameters. The bowl below the flare tapers (10°) 

 for nearly 0.42 total length, the diameter at the lower end 

 being 0.72 oral diameter. Below the taper the bowl becomes 

 conical (32°) for i.i oral diameters. The lance is subuni- 

 formly thick (nearly 0.22 oral diameter) and its length is 

 almost 0.35 total length. The free tip is acutely angular. 



The wall reaches a thickness of about 0.07 oral diameter 

 suborally, and thins rapidly to less than three-tenths that 

 much in the lower bowl. There are thin laminae which 

 enclose rectangular, subequal, radial secondary prisms. The 

 surface has a mesh of small, rounded hexagons. 



Length, 215 to 234I-I. 



The character of the lance distinguishes this species from 

 others, save X. aciis. In actis the bowl is mildly swollen, and 

 the lance laterally contracted. 



Recorded from one station (131) in the California region, 

 in a pump sample taken at 50 meters. Frequency, minimum. 



Temperature, i3?98; salinity, 33.24; density, 25.00; pH, 

 8.39. 



Xystonella lohmanni (Brandt) Brandt 



Xystonella lohmanni, Kofoid and Campbell, 1929, pp. 236-237, 

 fig. 448. 



The large, rather thick-walled lorica, with long, pointed 

 lance, has a length of 7.5 oral diameters. The oral cuff is 

 submerged by the outer rim of the flattened suboral trough, 

 which has a diameter of 1.33 oral diameters. The long 

 bowl tapers (5°) with virtually no flare, or other more than 

 stricdy local and minor modification, for 0.48 total length, 

 and then becomes conical (27°) for 0.22 total length. The 

 concave, tapering lance (7°) has a length of 0.31 total 

 length. Its upper end has a diameter of 0.3 oral diameter, 

 and its free tip is sharply pointed. 



The wall has a thickness of 0.06 oral diameter across the 

 bowl and is thinner in the aboral cone and lance. There are 

 thin laminae and radial secondary prisms. The surface 

 hexagons are larger in the middle of the bowl than either 

 above or below, where they are small. The wall is rather 

 soft and easily deformed, the lance being much the more 

 rigid part. 



Length, 330 to 58o[.i. 



Xystonella lohmanni is distinctly more elongated than X. 

 actts. It is also longer than X. lanceolata, and has a tapering 

 lance, whereas lanceolata has a tubular one. The lance in the 

 shorter X. longicauda is needle-like. 



Recorded from seven stations, five in the Atlantic and two 

 in the Pacific, as follows: one (16) in the Gulf Stream, two 

 (19, 20) in the Sargasso Sea, two (24, 27) in the Atlantic 

 equatorial region, one (70) in the Galapagos region, and one 

 (136) in the California region. 



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

 taken at 50 meters and 5 at 100 meters. Maximum fre- 

 quency, 4 per cent at station 136; other records above mini- 

 mum (2 to 3 per cent) from stations 19, 70; average in 

 Pacific net samples, 3.3 per cent. 



Temperature: Atlantic, pump sample 23^64, net samples 

 i8?o8-26?04 (22?92); Pacific, net samples i2?73-i8?87 

 (i5?8o). Salinity: Atlantic, pump sample 36.41, net samples 

 36.00-37.15 (36.53); Pacific, net samples 34.76-35.02 (34.89). 

 Density: Atlantic, pump sample 24.84, net samples 23.98- 

 26.06 (25.12); Pacific, net samples 25.09-26.28 (25.68). pH: 

 Atlantic, pump sample 8.23, net samples 8.09-8.30 (8.20); 

 Pacific, net samples 7.68-8.39 (8.03). 



Xystonella minuscula Kofoid and Campbell 



Xystonella minuscula Kofoid and Campbell, 1929, p. 237, fig. 

 453- 



The rather large lorica, with fairly short, conical bowl and 

 long pedicel, skirt, and lance, has a length of 5.4 oral diam- 

 eters. The thin oral cuff is submerged by the outer edge of 

 the concave trough. The outer edge of the trough has a 

 diameter of 1.42 oral diameters and is minutely serrate. The 

 upper bowl is truncate conical (16°) with little trace of flare, 

 local concavity, or swelling; the length of this cone is 0.4 

 total length, and its diameter at the lower end is nearly 0.67 

 oral diameter. The lower bowl is wider conical (within 

 24°), with a length of about 0.24 total length. The pedicel 

 is laterally concave tubular, with a length of 0.23 total length, 

 and with an expanded skirt with downward-projected 

 prongs. The lance is spikelike, sharply pointed at the free 

 tip, and 0.75 oral diameter in length. 



The wall is thickest suborally, where it reaches 0.18 oral 

 diameter; it rapidly thins in the lower bowl to much less. 

 There are thin laminae and enclosed radial secondary prisms, 

 which in their turn enclose small alveoles. The surface has 

 a more or less uniform pattern of small hexagons. The 

 lumen reaches to the lance. 



Length, 268 to 350^. 



Xystonella minuscula has a shorter, more conical bowl 

 than X. trejorti, with little or no suboral flare and concavity. 

 It lacks the spiral shelf of X. scandens, but in other ways is 

 similar. The remaining species lack a skirt. 



Recorded from three stations, two in the Atlantic and one 

 in the Pacific, as follows: two (27, 28) in the Atlantic equa- 

 torial region and one (112) in the North Pacific middle lati- 

 tudes. 



There are i pump and 4 net samples, of which i was 

 taken at the surface, and 2 each at 50 and 100 meters. Fre- 



