TAXONOMY AND DISTRIBUTION 



117 



stays which apparently support the mcmbrane-Iike, ahnost 

 transparent wall between them. This faceted region is 

 laterally concave, but the diameter of the bowl at the lower 

 end reaches 1.15 oral diameters, so that there is general 

 swelling up to that level. Below this level the bowl con- 

 tinues to expand, reaching, at 1.54 oral diameters below the 

 rim, a diameter of 1.23 oral diameters. As the bowl con- 

 tinues aborally it gradually contracts within a moderately 

 convex cone (28°) and reaches a diameter at the lower end 

 of the cone of about 0.5 oral diameter. The aboral horn is a 

 narrow cone (18°) with a length of slightly over i.o oral 

 diameter, and its free tip is pointed. 



The wall is exceedingly thin and clear, being hardly 

 \isible at all except in rather dim illumination. The lumen 

 strictly follows the outer contour. 



Length, 75 to 102H. 



A few loricae have inserted riblets standing between the 

 main ribs, and in some others subsidiary riblets occur. 



Hofker's loricae (1931) have bulbose aboral ends and 

 hence do not belong to the clearly defined Dadayiella gany- 

 medes, but to D. bidbosa. As the aboral characters are 

 wholly unlike those of AmphurcUa, there is no reason to 

 assign these loricae to that genus, which is distinct. 



Dadayiflla ganymedcs differs from D. acntijoimis in 

 having fewer facets, a more cylindrical aboral horn, and a 

 more sharply set-ofif bowl. There is no bulb as in D. bulbosa, 

 nor spikes as in D. jorgensciii. The facets are not so long as 

 those of either D. cuspis or D. pachytoeciis, and the bowl is 

 not short and plump as in D. curtn. 



Recorded from twenty-seven stations, nine in the Atlantic 

 and eighteen in the Pacific, as follows: one (14) in the Gulf 

 Stream, one (21) in the Sargasso Sea, five (22, 23, 25, 29, 

 30) in the Atlantic equatorial region, two (31, 33) in the 

 Caribbean Sea, ten (40, 41, 43, 47, 69, 71, 72, 73, 78, 80) in 

 the Galapagos region, two (108, no) in the North Pacific 

 trade region, three (iii, 114, 117) in the North Pacific 

 middle latitudes, one (118) in the East Asiatic marginal sea, 

 one (149) in the California region, and one (152) in the 

 Pacific equatorial region. Dadayiella ganymedfs is a hardy, 

 widely distributed species, absent mainly from the coldest 

 waters. 



There are i6 pump and 19 net samples, of which 8 were 

 taken at the surface, 16 at 50 meters, and 11 at 100 meters. 

 Maximum frequency, 60 per cent at station 114; other 

 records above minimum (2 to 10 per cent) from stations 14, 

 29, 69, no, 114, 117, 149, 152; averages, 1.4 loricae in Pacific 

 pump samples, and 2.3 and 10.2 per cent in Atlantic and 

 Pacific net samples, respectively. 



Temperature: Atlantic, net samples i4?6o-27?88 (22^09); 

 Pacific, pump samples io?i8-26?96 ( 19^24), net samples 

 8?93-26?o6 (i8?39). Salinity: Adantic, net samples 35.59- 

 56.51 (36.09); Pacific, pump samples 33-61-35.95 (34.85), 

 net samples 34.06-36.03 (35.97). Density: Atlantic, net 

 samples 23.26-26.66 (25.00); Pacific, pump samples 23.20- 

 26.11 (24.10), net samples 23.75-26.50 (24.98). pH: At- 

 lantic, net samples 7.93-8.31 (8.17); Pacific, pump samples 

 7.92-8.34 (8.12), net samples 7.76-8.38 (8.10). 



Stelidiellinae Kofoid and Campbell 



Stelidieilineae Kofoid and Campbell, 1929, p. 321. 



This subfamily includes four genera, namely, Oimoscl/a, 

 Biiindticlla. Piostflidii-llii, and Stclidiclla. Only the first two 

 are found in the material of this expedition. 



ORMOSELLA Kofoid and Campbell 



Ormosclla Kofoid and Camplicll, iQiQ, p. 3:^2. 



This is an unusual tropical genus, often rare in the plank- 

 ton. 



One species is describeil here. 



Ormosella apsteini Kofoid and Campbell 

 Orniosrlla npstciiii Kofoid and Campbell, 1929, p. 323, fig. 620. 



The tall, narrow lorica, with conical collar, thin bowl, and 

 long, sharp aboral horn, has a length of 2.38 to 3.21 oral 

 diameters. The oral margin is thin and sharp. The conical, 

 sleevelike collar is sharply set off from the bowl; it is 0.38 

 oral diameter in width, flares (15°), and has flat sides. The 

 bowl has a maximum diameter, just below the collar, of 0.56 

 oral diameter. It decreases steadily in diameter as a trun- 

 cated basal segment of a pyramid (3°) in the upper 2.0 oral 

 diameters, and then 35° in the lower i.o oral diameter. The 

 bowl is faceted with 7 subequal, plane sides. The aboral 

 horn is a narrow, sharply pointed cone (4°) with a length 

 of 0.77 oral diameter in some instances. 



The wall is glassy, without prismatic structure but with 

 thin laminae and homogeneous enclosed substance. It thick- 

 ens from the oral margin to the lower end of the collar, 

 being there nearly o.i oral diameter across, and is somewhat 

 less thick in the bowl. The aboral horn is solid. 



Length, 100 to 13611. 



Ormosella apsteini has a narrower, more elongated bowl 

 than the other species. It is somewhat like O. schweyeri in 

 all characters save the elongation and the differently shaped 

 bowl. It has fewer facets than O. trachelium, has a less 

 stout bowl than O. bresslaui as well as a longer horn, and 

 hardly resembles the remaining species. 



Recorded from one station (74) in the Galapagos region, 

 in a net sample taken at 100 meters. Frequency, minimum. 



Temperature, i6?52; salinity, 35.14; density, 25.75; pH, 

 7.89. 



BRANDTIELLA Kofoid and Campbell 



Brandtiella Kofoid and Campbell, 1929, p. 325. 



Brandtiella is often very common in the tropical ocean. 

 There is but a single species. 



Brandtiella palliata (Brandt) Kofoid and Campbell 

 (Figures 126, 127) 

 HraiultiiUa palliata, Kofoid and Campbell, 1929, p. 325, fig. 623. 



The elongate, amphora-like lorica, with spool-shaped 

 collar, complexly folded aboral end, and outer gelatinous sac, 

 has a length of 3.53 to 4.12 oral diameters. The oral margin 

 is thin-edged, erect, and entire. The narrow, grooved, wheel- 



