TAXONOMY AND DISTRIBUTION 



47 



about 34 erect, triangular teeth. These teeth arise from a 

 narrow (0.02 oral diameter) hyaline cuff. The bowl below 

 the cuff expands concavely, giving rise to an angular ledge 

 of nearly 1.15 oral diameters, close to 0.15 oral diameter 

 below the rim. The bowl below the ledge is concave 

 cylindrical. This cylindrical part is nearly 0.4s oral diameter 

 in length, and at its lower end there is a ledgelike swollen 

 /one of about 1.2 oral diameters with a width of approxi- 

 mately 0.22 oral diameter; sometimes this zone is more 

 sharply marked and not so wide. The bowl contracts below 

 this second ledge as an inverted basal segment of a hollow- 

 sided truncate cone (27 ) with a diameter, at its lower end, 

 of 0.94 oral diameter. The aboral region again contracts as 

 a concave cone (76 ) with a width of 0.=; oral diameter, and 

 the broadly rounded aboral end has a diameter of nearly 

 0.25 oral diameter. 



The wall is homogeneous, and its structure is difficult to 

 make out. Its thickness hardly exceeds 0.01 oral diameter, 

 even in the ledges. The cavity partially enters the ledges 

 and the horn. The surface shows hexagonal meshwork and 

 is weakly pitted. It is denser aborally than elsewhere. 



Length, 77U.. 



The Carnegie loricae are more like those of Hada (19326) 

 than those of Brandt in size, proportions, and other charac- 

 ters; perhaps there is some geographical difference. 



Ptychocylis drygalskji resembles P. obtusa, but it is stouter 

 and its aboral end is not similar. It bears some likeness to 

 P. arctica, but is shorter and stouter and has a less bullet- 

 shaped bowl than that species; arctica has a narrower conical 

 aboral region and pointed tip. 



Recorded from one station (123) in the East Asiatic mar- 

 ginal sea, in a pump sample taken at the surface. Frequency, 

 minimum. 



Temperature, 8? 10; salinity, 32.76; density, 25.52; pH, 

 8.03. 



Ptychocylis minor Jorgensen 

 Ptychocylis minor, Kofoid and Campbell, 1929, p. 188, fig. 354. 



The rather short, urn-shaped lorica, with conical aboral 

 region and short horn, has a length of 1.7 oral diameters. 

 The oral margin is regularly provided with about 56 short, 

 erect, bluntly pointed, evenly spaced, triangular teeth resting 

 on a narrow, hyaline cuff, the width of which is only 0.01 

 oral diameter. The bowl expands (8o°) to a narrow, pro- 

 jecting shelf or ledge, the diameter of which is 1.18 oral 

 diameters, and which is at 0.11 oral diameter below the rim. 

 Below this shelf the bowl contracts with concave lateral con- 

 tour to a swollen zone (1.08 oral diameter) with a width of 

 0.22 oral diameter, near 0.5 oral diameter below the rim. 

 Below this swelling the bowl contracts as an inverted trun- 

 cated, barely concave cone (16°) with a width of 0.39 oral 

 diameter, and a diameter at its lower end of 0.92 oral diam- 

 eter. The aboral region is an inverted hollow cone (90 ), 

 with a width equal to that of the region just above it, and a 

 diameter of 0.21 oral diameter at the lower end. The aboral 

 horn is a narrow cone (30°), with a length of 0.34 oral 

 diameter. Its tip is minutely rounded. 



The wall has thin laminae, and two to five layers of tiny, 



hexagonal prisms are thus enclosed. The wall is thickest 

 suborally and in the horn, where it reaches nearly 0.05 oral 

 diameter; elsewhere it is about hall as thick. The outer sur- 

 face is rather coarsely reticulated with pitted hexagons; these 

 pits are especially developed in the shell and aboral cone. 



Length, 90 to 13511. 



Some of the Carnegie loricae contract with sharp angles 

 suborally and have decided conical bowls and bluntly conical 

 horns. 



Ptychocylis minor most resembles /'. urnula, but is shorter, 

 with less conical aboral region and more conical bowl. The 

 horn is also shorter and more conical. Ptychocylis acuta has 

 a shorter horn; P. repanda and P. ostenjeldi are similar. 



Recorded from seven stations in the Atlantic, as follows: 

 one (7) in the North Sea, four (8, 9, 10, 11) in the Atlantic- 

 drift, one (12) in the American cold-water region, and one 

 (14) at the margin of the Gulf Stream. 



There are 2 pump and 14 net samples, of which 6 were 

 taken at the surface, 6 at 50 meters, and 4 at 100 meters. 

 Maximum frequency, 100 per cent at station 10 at the sur- 

 face; other records above minimum (2 to 80 per cent) from 

 stations 7, 8, 9, n, 12, 14; averages, 5.5 loricae and 53.2 per 

 cent in pump and net samples, respectively. 



Temperature: pump samples 7?oi-8?44 (7^72), net 

 samples 4?i8-i4?02 (8^96). Salinity: pump samples 33-65- 

 34.97 (34.31), net samples 34.51-35-59 v35-°2)- Density: 

 pump samples 26.16-27.42 (26.79), net samples 26.66-27.96 

 (26.96). pH: pump samples 7.92-8.10 (8.01), net samples 

 7.92-8.08 (8.00). 



Ptychocylis obtusa Brandt emended Kofoid and Campbell 



(Figures 57, 58) 



Ptychocylis obtusa, Kofoid and Campbell, 1929, pp. 188-189, 

 fig. 349; Schulz and Wulff, 1929, pp. 336-338, figs. 105-109; 

 Bernstein (part), 1931, pp. 13-14, fig. 2a, b (for fig. zc-g see 

 P. glacialis and P. urnula); Hada, 1932^, pp. 55-56, fig. 21; 

 19326, p. 567. 



The stout, squat lorica, with aboral cone and flattened end, 

 has a length of 1.57 oral diameters. The oral margin is 

 regularly serrate with minute, evenly spaced triangular 

 points, and these rest on a very narrow, clear band the width 

 of which is only 0.02 oral diameter. The bowl expands con- 

 cavely and conically (60°) for a distance of 0.14 oral diam- 

 eter and reaches 1.13 oral diameters at its lower end. It 

 again contracts conically (50 ) and reaches a diameter of 

 1.04 oral diameters at 0.26 oral diameter below the rim. 

 Once again it expands conically (60°), reaching a diameter 

 of 1.22 oral diameters near 0.43 oral diameter below the rim. 

 Below this level the bowl contracts conically (65°), reaching, 

 at 0.55 oral diameter below the rim, a diameter of 1.07 oral 

 diameters. This last diameter is maintained for a distance 

 of 1. 12 oral diameters below the rim, giving the central 

 region of the bowl a generally cylindrical contour. At the 

 lower end of this cylinder the bowl contracts conically (8o°) 

 once more for 0.24 oral diameter, reaching a diameter of 

 0.68 oral diameter at the lower end of this zone. The pedicel- 

 like region is a truncated cone (45°) with a length of 0.43 



