4 8 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



oral diameter. Its lower end is squarely truncated and its 

 width is 0.4 oral diameter. The sides of this much contracted 

 lorica are neatly rounded over the several shoulders, and the 

 conical regions are generally full or convex. 



The wall is usually thin, hardly exceeding 0.01 oral diam- 

 eter, with some slight thickenings at the angles. Laminae 

 and alveolar structure are not distinguished. The outer 

 surface is reticulated, however, with elongate hexagons, and 

 near the aboral end it is pitted, the walls of the reticulations 

 being lifted above the general surface. The lorica is dark 

 and heavy. 



Length, 119(1. 



These extremely numerous loricae are decidedly variable. 

 One extreme form is shown (fig. 58). Schulz and Wulff 

 (1929) illustrate a long series taken in different temperatures 

 and other physical conditions in the Barents Sea; these loricae 

 all differ widely. 



Ptychocylis obtusa resembles P. cylindrica, but the cylin- 

 drical part of the bowl is not so long and the lorica is much 

 stockier. The character of the aboral end differentiates obtusa 

 from the other species, for none of them has a wide, flat 

 end; their ends are, for the most part, either acute or pointed. 



Bernstein (1931) included P. glacialis and P. urnula in 

 obtusa. Some of Schulz and Wulff's loricae (1929) belong 

 elsewhere (especially in P. cylindrica), although not distin- 

 guished here. The genus needs special study. 



Recorded from thirteen stations, three in the Atlantic and 

 ten in tht Pacific, as follows: one (7) in the North Sea, one 

 (10) in the Atlantic drift, one (13) in the American cold- 

 water region, two (116, 117) in the North Pacific middle 

 latitudes, six (118, 119, 120, 121, 122, 123) in the East Asiatic 

 marginal sea, and two (124, 125) in the Alaskan secondary 

 region. The species is distinctly circumpolar. 



There are 18 pump and 21 net samples, of which 10 were 

 taken at the surface, 15 at 50 meters, and 14 at 100 meters. 

 Maximum frequency, 91 per cent at station 125; other records 

 above minimum (2 to 79 per cent) from stations 13, 116, 

 117, 120, 121, 122, 123, 124. Records of 2 to 300 loricae 

 occur in pump samples; average frequencies in net samples, 

 15 and 44.2 per cent in Atlantic and Pacific, respectively. 



Temperature: Atlantic, pump sample n?27, net samples 

 1? 64-11? 27 (7^72); Pacific, i?72-io?50 (5?og) and 2?oi- 

 i8?i8 (5?8o), respectively. Salinity: Atlantic, pump sample 

 32.68, net samples 32.68-35.24 (34.06); Pacific, 32.73-33.72 

 (33.00) and 32.73-34.06 (33.12), respectively. Density: At- 

 lantic, pump sample 24.94, net samples 24.94-27.96 (26.81); 

 Pacific, 25.13-26.52 (25.48) and 25.52-26.76 (26.16), respec- 

 tively. pH: Atlantic, net samples 8.04; Pacific, pump samples 

 7.86-8.21 (7.95), net samples 7.64-8.1 1 (7.97). Records of 

 pH were not available for the Atlantic pump sample, but 

 were available for 2 of the net samples, each 8.04. 



Ptychocylis urnula (Claparede and Lachmann) Brandt 

 Ptychocylis urnula. Kofoid and Campbell, 1929, pp. 189-190, 

 fig. 355; Schulz and Wulff, 1929, pp. 336-338, figs. 111-114. 

 Ptychocylis obtusa, Bernstein (part), 1931, pp. 13-14. rig. 2/, g 



(for fig. la-e see P. obtusa and P. glacialis) . 

 The generally cylindrical lorica, with conical aboral end 



and elongated, pointed horn, has a length of 1.93 oral diam- 

 eters. The oral margin is regularly set with about 60 sharp, 

 erect, evenly spaced, triangular teeth, which arise from a 

 hyaline cuff with a width of less than 0.02 oral diameter. 

 The bowl swells concavely to a suboral ledge of 1.17 oral 

 diameters at 0.1 oral diameter below the rim. Below the 

 ledge it assumes a barely concave cylindrical shape for a 

 distance of 0.37 oral diameter below the rim, at which level 

 a second, less pronounced and distinctly rounded, ledge 

 occurs. This ledge has a diameter of 1.06 oral diameters and 

 occupies a zone with a width of approximately 0.14 oral 

 diameter. The bowl below this zone becomes subcylindrical 

 for 1.0 oral diameter and again swells slightly, reaching a 

 diameter a little greater than that of the oral margin. Below 

 this level the bowl contracts as a plane or barely concave 

 cone (62 ) with a length of 0.68 oral diameter. At its lower 

 end is the aboral horn, which is a narrow, sharp, pointed 

 cone (26 ) with a length of nearly 0.26 oral diameter. 



The wall is thick, being 0.06 oral diameter across the 

 upper ledge, where it is thickest; elsewhere it is only about 

 a third as much. The cavity follows the outer contour, enter- 

 ing into the upper bulge and extending to the tip of the 

 horn. The wall is denser aborally and its surface is finely 

 reticulated with irregularly formed hexagonal prisms, the 

 walls of which are raised so that the bowl appears pitted. 



Length, 123 to 192^. 



Variations in length are probably correlated with tem- 

 perature. Some loricae have longer horns than others, but 

 the general shape is retained. 



Ptychocylis urnula resembles P. minor, but is longer and 

 has a more conical aboral region and a thinner and longer 

 horn. Its bowl is also more cylindrical. Its horn is not so 

 long as that of P. repanda or P. ostenfeldi, and the bowls of 

 these two species are very different. Ptychocylis wailesi has 

 a concave-conical lower bowl and lacks a prolonged horn. 

 Other species have rounded aboral ends and are not closely 

 related. 



Bernstein ( 1 93 1 ) unites urnula and obtusa in his figures, 

 but distinguishes one lorica in his text as urnula (fig. 2g). 



Recorded from one station (10) in the Atlantic drift, in a 

 net sample taken at 100 meters. Frequency, minimum. 



Temperature, 6^56; salinity, 35.02; density, 27.52; pH, 

 7-95- 



PETALOTRICHIDAE Kofoid and Campbell emended 

 Petalotrichidae, Kofoid and Campbell, 1929, p. 190. 

 Included in this family are three genera: Craterella, Acan- 

 thostomella, and Petalotricha. All three genera occur in the 

 material of this expedition. Petalotricha is exclusively a 

 warm-water genus, the others being more widely spread, 

 often into very cold waters. 



Craterellinae Kofoid and Campbell 

 Craterellineae Kofoid and Campbell, 1929, p. 190. 

 Two genera belong to this subfamily: AcanthostotneUa 



and Craterella. 



