74 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
they form an outer lower lip. Each consists of an inner 
rectangular plate spinose at its anterior margin, and an 
outer five-jointed palp. The joints of the palp are spinose, 
each of the four distal joints having on its inner side a 
setose pad. At the base there is a small lamella. 
The pereiopods (Pl. Il., figs. 8, 9) or ambulatory 
appendages. Hach pereiopod consists of a basal protopodite 
and an endopodite, which is composed of five spinose joints 
(ischiopodite, meropodite, carpopodite, propodite and 
dactylopodite). In the posterior pairs of pereiopods, the 
carpopodite and propodite are long in comparison with 
the other joints. The dactylopodite bears two strong re- 
curved claws. 
In the female each of the anterior five pairs of 
pereiopods (Pl. II., fig. 12) subtends a thin foliaceous 
lamella which curves downwards and inwards, overlapping 
the opposite and adjacent lamellae, and thus they form a 
brood pouch in which the eggs are carried. These lamellae 
are not out-growths of the limbs, but of the sterna. 
Abdominal appendages. ‘here are five pairs of 
abdominal appendages or pleopoda, and a terminal pair of 
uropoda. Each pleopod (PI. IL., figs. 11, 15) consists of a 
pear-shaped superior lobe covering a small inferior lamella. 
In the terrestrial isopods, the outer lobe is termed 
opercular and the inner branchial. In Ligia both are 
branchial, as will be shown later. 
At the base of the outer edge of the superior lobe, 
there is a small lamella. The edge of the superior lobe is 
fringed with a border of setose bristles. The second pair 
of pleopods are modified in the male by having a two- 
jointed style arising at the base of the inner margin of 
the superior lobe (Pl. IL., fig. 10). The style is long and 
grooved, and reaches to the fourth pleopod; its distal 
extremity is slightly swollen and finely pointed. It is 
