54 



OCEANIC TINTINNOINA OF LAST CRUISE OF CARNEGIE 



Atlantic, pump samples 35.10-36.75 (35.82), net samples 

 35.88-37.05 (36.20); Pacific, 34.30-36.46 (35.01) and 33.36- 

 36.24 (35.11), respectively. Density: Atlantic, pump samples 

 25.86-26.34 (26.09), nst samples 23.26-27.01 (25.42); Pacific, 

 22.43-25.48 (24.29) and 22.31-26.50 (24.69), respectively. 

 pH: Atlantic, pump samples 7.96-8.20 (8.1 1), net samples 

 7.93-8.28 (8.23); Pacific, 8.08-8.34 (8.20) and 7.76-8.39 

 (8.21 ), respectively. 



Petalotricha serrata Kofoid and Campbell 

 Petalotricha serrata Kofoid and Campbell, 1929, p. 205, fig. 3iS6. 



The lorica, with definitely serrated oral margin and a 

 saccular aborally pointed end, has a length of r.r oral diam- 

 eters. The oral margin has 48 short, sharp, erect, triangular 

 teeth. The upper collar flares (80°) and its width is 0.09 

 oral diameter. Its lower edge is marked by a single row of 

 small, ovoid lacunae with horizontal axes. The lower collar 

 has a width of 0.12 oral diameter and is a band or cuff with 

 plane sides; it is differentiated only by being optically less 

 dense than the bowl. There is scarcely any nuchal con- 

 striction, and the bowl below reaches 0.9 oral diameter at a 

 similar distance below the margin. It contracts (26°) below 

 the level of maximum diameter for a distance of two-thirds 

 its own length, and again more so (100°) below this to the 

 aboral end. The aboral end is distinctly pointed, with a 

 tiny nipple. 



The gray wall is thin and has but a single layer of prisms 

 between the laminae. There are 17 large equatorial lacunae. 



Length, 105 to i2o|i. 



Petalotricha serrata resembles P. umpidla, but the oral 

 teeth are regular and pronounced. It has a cylindrical lower 

 collar, and unlike ampulla has scarcely any nuchal contrac- 

 tion. Its bowl is pointed, unlike that of P. major, and is 

 longer than that of P. pacifica, but not so long as that of 

 P. indica. Petalotricha capsa has definite many-layered 

 alveolar walls, lacking in serrata. 



Recorded from two stations, one each in the Atlantic and 

 the Pacific, as follows: one (30) in the Atlantic equatorial 

 region, and one (46) in the Galapagos region. 



There are 2 net samples, one each from 50 and 100 

 meters. Frequency, minimum. 



Temperature: Atlantic, 25?54; Pacific, 23?26. Salinity: 

 Atlantic, 36.40; Pacific, 35.33. Density: Ariantic, 24.25; 

 Pacific, 24.13. pH: Adantic, 8.28; Pacific, 8.16. 



RHABDONELLIDAE Kofoid and Campbell 



Rhabdonellidae Kofoid and Campbell, 1929, p. 206. 



Included in this family are four genera: Protorhabdonella, 

 Epirhabdonella, Rhabdonclhi, and Rhabdonellopsis. Three 

 are found in the material of this expedition, and all are 

 tropical to subtropical. 



PROTORHABDONELLA Jorgensen 



PrntorlnihdoiuUa, Kofoid and Campbell, 1929, p. 206. 



Protorhabdonella is clearly the simplest genus of the Rhab- 

 donellidae in size and form. Kofoid and Campbell (1939, 



p. 158) erected a new genus, Epirhabdonella, with two new 

 species, also related but with finlike ribs. 



Protorhabdonella is almost exclusively tropical and oceanic, 

 being most common in southern waters. 



Three species are described here. 



Protorhabdonella curta (Cleve) Jcirgensen 



Protorhabdonella airlii, Kufoid and Campbell, 1929, p. 207, fig. 

 393; Marshall, 1934, p. 646. 



The tiny conical lorica, with numerous twisted ribs and 

 pointed aboral end, has a length of 1.8 oral diameters. The 

 oral margin is thin-edged and narrow, and an exceedingly 

 low cuff surrounds it. The conical bowl is 12° in the upper 

 half and increases to 68° in the lower part. There is a low, 

 rounded shoulder a little below the oral margin, the diameter 

 of which is 1.2 oral diameters; at its middle the bowl is 

 slightly less than i.o oral diameter. The upper bowl is 

 barely convex, but the lower is distinctly concave. The aboral 

 end is pointed, and conical (16°) but not especially pro- 

 longed. There are about 24 strongly left-turned (15°), very 

 low, linelike ribs. These ribs are rarely or never branched, 

 and die away some distance below the suboral shoulder; 

 they converge at the aboral end. Fenestrae are lacking. 



The exceedingly thin wall is transparent. 



Length, 39 to 521.1. 



Protorhabdonella curta differs from P. simplex chiefly in 

 having more ribs that are strongly twisted, in contrast with 

 the fewer vertical ones of the other species. Differences in 

 shape are less marked, but some are of importance. Al- 

 though it has numerous ribs, it is not like Rhabdonella exilis, 

 R. indica, or R. amor, all forms with longer, narrower bowls 

 and emergent horns. 



Recorded from four stations, one in the Atlantic and three 

 in the Pacific, as follows: one (31 ) in the Caribbean Sea, two 

 (54, 60) in the South Pacific middle latitudes, and one (113) 

 in the North Pacific middle latitudes. 



There are 4 net samples, of which i was taken at the 

 surface and 3 at 100 meters. Frequency, 4 per cent at station 

 113, and 2 per cent at station 54; other records minimum; 

 average in the Pacific, 2.3 per cent. 



Temperature: Atlantic, 22?56; Pacific, i4?97-2i?74( 1 8?48). 

 Salinity: Atlantic, 36.51; Pacific, 33.91-35.35 (34-64). Den- 

 sity: Adantic, 25.22; Pacific, 24.06-25.37 (24.86). pH: At- 

 lantic, 8.19; Pacific, 8.07-8.23 (8.15). 



Protorhabdonella simplex (Cleve) Jorgensen 

 (Figures 83, 84) 

 Protorhabdonella simplex, Kofoid and Campbell, 1929, p. 208, 

 fig. 395; Marshall, 1934, p. 646. 



The short, conical lorica, with low, hyaline collar, few 

 bladelike iins, and pointed aboral end, has a length of 2.18 

 oral diameters. The oral rim is simple, thin, and erect. The 

 low collar is a cuff with a length of little more than 0.0 1 oral 

 diameter. The conical bowl is about 9° within the upper 0.9 

 oral diameter, and increases to 42° in the lower 1.32 oral 

 diameters. Just below the collar is a barely evident rounded 

 shoulder, the diameter of which is 1.18 oral diameters; at the 



