The thoracic feet (Fig. 3) are about 1.5 mm. in length, eight in number and biramous. The outer margins are heavily covered with hair, while the inner margins are comparatively smooth. The first four abdominal appendages (Figs. 5, 6) are much larger than the thoracic feet, being 2.5 mm. in length, and are used for swimming, like those of the copepods. They are also biramous, the back margin and tip having numerous hairs along the edge, while the inner margins are lined with many plumous hairs. The first appendage (Fig. 5) is somewhat heavier than the fourth (Fig 6), but the hairs and spines are arranged in the same relative position. The fifth appendage (Fig. 7) is two-jointed uniramous and small, .9 mm. long. The sixth is one jointed and smaller yet.
The eight abdominal segments taper off in size and the last bears a pair of caudal styles (Fig. 8) which are lined with sharp spines along their outer margins. The ends of the styles are armed with two long, sharp spines.
(Contribution from the Zoological Laboratory of Pomona College.)
EXPLANATION OF PLATE I
Magnification 25 Times
Figure 1. Nebalia bipes.
EXPLANATION OF PLATE II
Magnification 25 Times
Figure 2. Antennæ.
Figure 3. Mandibular palp.
Figure 4. Thoracic appendage.
Figure 5. First abdominal appendage.
Figure 6. Fourth abdominal appendage.
Figure 7. Fifth abdominal appendage.
Figure 8. Caudal styles.