1 6 
TH. MORTENSEN, 
(Schwed. Südpolar-Exp. 
The radial is very low, just a narrow ridge remaining in the middle, while the 
interradial edges are rather high. The costal is low, with rounded lateral edges, not 
in apposition laterally. Axillaries as broad as long. The shape of the primibrachs 
and lower brachialia is shown in PI. V, Fig. i. The sides are rounded. The primi- 
brachs and brachials are smooth, the latter only with a series of short thorns along 
the raised outer edge; this raised edge gives the arms a serrate outline in side view 
(Figs. 15 a — b). Syzygies on joints 3, 8, 12, 14, 16, and probably continuing on 
every second joint towards the end of the arm. 
The first pinnule is ca. 3 — 4 mm. long, with 14 slender, somewhat 
elongated joints, the distal edge of which is set with thorns; no terminal 
comb (PI. V, P'ig. 1). P 2 is exactly like Pj, but carries a genital organ. 
P-j and P 4 a little shorter and with only 9 joints; they have no ambulacral 
furrow, and thus really are oral pin- 
nules, although carrying genital or- 
gans. The first true arm-pinnule, P 5 , 
has 10 joints and is 3,5 mm. long. 
P 7 is slightly longer and has 1 1 joints; 
this has no genital organ. All the 
pinnules have the distal end of the 
joints thickened and thorny (PI. V, 
Figs. 2 — 5). No pinnules preserved 
beyond the 7th — 8th. 
Disk naked; anal cone high, 
situated near the oral corner of its 
interradius. Ambulacral furrow on 
the basal part of the arms very in- 
conspicuous, merely a narrow, shallow 
furrow, apparently devoid of tentacles. 
Farther out, from about the fourth 
pinnule, the tentacles are distinct. 
Sacculi few and inconspicuous on the disk and lower part of the arms, farther 
out more numerous; on the genital pinnules they are somewhat irregularly arranged, 
on the distal pinnules they are quite regularly arranged and fairly conspicuous. 
Side plates and cover plates are entirely absent from the ambulacral furrows, and 
there are no spicules in the tentacles. 
Color in alcohol whitish. 
Only a single, small, poorly preserved specimen was taken at Station 59 (53 41' S. 
61 10' W., 137 — 150 m.) on the Burdwood bank. 
Fig. 14. 
Young cir- 
rus of Th. 
nutrix. 2? /i. 
Fig- 1 5 - a - Side view of armplates from the 
proximal part of the arm. b. Dorsal view 
of armplates from the distal part of the arm, 
of Th. nutrix. 31 fr. 
