LIGIA. io 
largest; the fifth joint equals in length the proximal five 
joints of the flagellum. The flagellum may have as many 
as 13 or 14 joints, which are setose, the setae being of two 
sizes. 
The mandibles (PI. I1., figs. 8, 4) are very powerful and 
consist of a single protopodite. The point of attachment 
is D shaped, the curve being internal. From the anterior 
end of the external border, a powerful tooth-bearing 
process curves inwards, forming a quadrant-shaped 
anterior face. The curve of the quadrant is external; 
the lower side is partially attached and the vertical side 
bears the mandibular processes. Internally, on this 

yertical side, there are—a stout molar process, the flat 
extremity of which is covered with minute closely-set 
teeth; a small palpiform structure bearing setose bristles, 
and two stout mandibular teeth separated by a sinus, each 
being sub-divided into three smaller teeth. The ventral 
edge of the mandible is produced into a rounded keel, 
which gradually diminishes in depth towards the posterior 
edge. 
The first pair of maxillae (PI. I1., fig. 5). Hach maxilla 
is composed of two lobes. The outer lobe is calcified and 
much stronger than the inner, which is more flexible. 
The inner lobe is terminated by three deflexed setose 
bristles; the outer lobe has a terminal group of short 
thick spines. 
The second pair of maxillae (PI. II., fig. 6) are much 
modified, being thin and flexible. Hach consists of a long 
protopodite, terminated by an oblique setose joint 
having internally at its base two setose bristles. The 
maxillary excretory organ opens at the base of the 
protopodite. 
The maxillipedes (PI. II., fig. 7) are closely approxi- 
mated on their inner sides and joined at the base, so that 
