150 ANNALS OF SCOTTISH NATURAL HISTORY 
provided with numerous sete; the proportional length of 
the joints are nearly as shown by the annexed formula :-— 
eee ease y 5h KO, 7 
Posterior antenne four-jointed ; the first and second joints are 
elongate, the third and fourth very short (Fig. 3). Mandible 
short and moderately stout, armed at the extremity with 
two processes and two spiniform sete ; one of the processes 
is conical and toothlike, and serrate on the inner edge, the 
other is somewhat cylindrical, and rounded at the end—the 
margin that is opposed to the tooth-like process, and also 
the end, being hispid (Fig. 4). Maxilla stout, broad, and 
bearing a number of terminal spiniform sete. Anterior foot- 
jaws stout, with a proportionally large marginal setiferous 
lobe, and several terminal spines (Fig. 5). Posterior foot-jaws 
two-jointed, those of the male armed with a strong, uncinate, 
and sinuous terminal claw, which is considerably longer than 
the stout broad joint from the end of which it springs, and 
with which it forms a powerful grasping organ. At the base 
of the claw, on the inside, there is a stout, short, and blunt 
spine. The inner edge of the last joint of the foot-jaw is fur- 
nished with a double (?or treble) row of elongate blunt- 
pointed teeth. Two long stout plumose sete spring from the 
inner margin, and near the distal end of the first joint. The 
terminal claw probably passes down between these two sete, 
and. forms with them an interlocking apparatus (Fig. 7). 
The posterior foot-jaws in the female, are also moderately _ 
stout, but the terminal claw is feeble ; the last joint is not so 
broad, and its inner margin bears two setiferous spines instead 
of the double row of teeth possessed by that of the male. 
The first, second, third, and fourth pairs of swimming-feet 
are nearly alike ; both branches are short (the outer being 
rather shorter than the inner) and three-jointed. The outer 
branch is armed exteriorly with a number of dagger-like 
spines, as shown in the figures (Figs. 8 and 9). The inner 
distal angle of the first basal joint of all the four pairs bears 
a spiniform seta. The inner distal angle of the second basal 
joint of the first pair bears also an elongate dagger-like spine, 
while a moderately long and stout seta springs from the 
outer margin of the same joint. The fifth pair of feet are 
