938 
Length of ‘Siboga’ females 2,9 mm. 
The known distribution at present is very limited. 
3. Scaphocalanus elongatus nov. sp. Plate XXXII, figs. 10—16. 
Female — length 2,9 mm. 
Seen from above, the body is elongate and narrow. The head is fused with the first 
thoracic segment, and its combined length is nearly twice that of the three following segments 
together. The fourth and fifth thoracic segments are completely fused. The last thoracic segment 
is slightly produced and is distinctly pointed. Viewed from the side, the forehead appears narrowly 
rounded. The last thoracic segment terminates in a small but distinctly curved point. The rostrum 
is represented by two long slender filaments (Plate XXXII, fig. 13). 
The abdomen is composed is four segments. The combined length of the abdomen and 
furca is contained two and two-third times in the total length of the cephalothorax, from the 
frontal margin to the base of the genital segment. The genital segment is slightly longer than 
the second segment, and the anterior portion of the ventral surface is slightly produced. The 
second and third segments are of equal length. The anal segment is equal to two-thirds of 
the length of the third segment. The furcal joints are fully twice as long as broad, and are 
slightly longer than the anal segment. 
The antennules were incomplete. 
The antennae, mandibles, maxillae and maxillipedes are similar to those of Scaphocalanus 
Magnus. 
The four pairs of swimming feet are also similar to those of that species. 
The fifth pair of feet consists of two free joints attached to a basal part. The first joint 
is short. The second joint is of moderate length, and it is considerably contracted from the 
middle to the apex. The inner marginal spine arises from the middle of the joint, and is fully 
twice as long as the joint. The apical spine is equal to half of the length of the inner spine. 
The outer marginal spine is placed near the apex, and is contained two and a half times in 
the length of the apical spine. The outer marginal spine of the right foot is wanting, but this 
is probably accidental. 
This species is easily distinguished from the other members of the genus, by the distinctly 
pointed last thoracic segment when seen in side view, and by the shape of the second free 
joint of the fifth foot. The forehead is faintly thickened in the middle line, which may indicate 
a very weak crest, but the material was too limited to make certain. 
Occurrence. — One female was found in the plankton collected with the HENnsEN 
vertical net at Station 148, 1000 metres to the surface. 
Genus Lophothrix Giesbrecht, 1895. 
The members of this genus are distinguished by the very short end joint of the exopodite 
of the antennae, and by the stout bifurcate rostrum. The rami of the rostrum terminate in a 
small spine, but there is no articulation between the spine and the basal portion. The female 
98 
