38) 
Clausocalanus furcatus Cleve, 1903, p. 360. 
Clausocalanus furcatus Cleve, 1904, p. 188. 
Clausocalanus furcatus Sars, 1905 (a), p. 3. 
Clausocalanus furcatus Wolfenden, 1905 (a), p. 999. 
Clausocalanus furcatus appeared to be almost as widely distributed in the region 
traversed by the ‘Siboga’, as the previous species. The following is the record of the stations 
where it was noted. 
Sat WO, —= Sw, AO, == Stem, 81, —= Sia, oo(Gay, — Sia o6 (meni), — Sia, of — 
Si@i, OG, —= Stati, 1i@, —= Grate, 12, —=' State, 118s == Stat, nar, —= Sie, 128, = Sime, 198) — 
Si@iis idl. —= Stat, 14a, —= _ Steaie, AZ. — Stas WAS, —= Sheaves, 16S —— Stee 11, = Siete, 15, = 
Stat. 203 (surface). — Stat. 203 (1500 metres to surface). — Stat. 204. — Stat. 205. — 
State 2iigh | Stat. 205") —- Stat 217 (horizontal cylinder). — Stat. 220) (vertical net); — 
SWE 221o —= Sali, BRO —= Siiat, Big == Sele, 270, —= Get, B82, <=" Siete, its. 
The females of this Clausocalanus, are distinguished from those of Clausocalanus arcut- 
cornis, by the genital segment being shorter than either of the next two segments, and by the 
furcal joints being twice as long as broad. 
This species has a similar distribution in the great oceans as the previous one. 
Genus Oxycalanus Farran, 1908. 
This genus was established by G. P. Farran in 1908, for the reception of a Calanoid 
nearly related to Spznocalanus, but the possession of a strong bifurcate rostrum at once separates 
it from that genus. . 
A number of specimens of a form apparently belonging to this genus, were found in the 
‘Siboga’ plankton. I was inclined at first, to regard them as identical with Farran’s species, but 
further consideration revealed some important differences, which appear worthy of specific rank. 
Only one species belonging to this genus was observed. 
1. Oxycalanus semtspinus nov. sp. Plate II, figs. g—21. 
Female — length 2,4 mm. 
The cephalothorax is oblong ovate in dorsal view, and is slightly contracted in front. The 
head is completely fused with the first thoracic segment. The fourth and fifth thoracic segments 
are fused together. The lateral margins of the last segment are rounded, and slightly produced 
posteriorly. The rostrum is well defined, and is produced into two sharp points (Pl. H, fig. 11). 
The abdomen is four-jointed, and is equal to rather more than one-third of the length 
of the cephalothorax. The genital segment is asymmetrical. This is due to a slight protuberance 
on the right side. It is equal to the combined length of the second and third segments. The 
third segment is slightly shorter than the second. The anal segment is equal to two-thirds of 
the length of the third segment. The furcal joints are slightly longer than broad, and are about 
as long as the anal segment. 
The antennules are twenty-four-jointed and reach to the anal segment. The terminal joint 
is very small, and is furnished with one sensory filament. 
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