LIGIA. 73 



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 (PL II., figs. 3, 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 

 vertical 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. II., fig. 5). Each 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 (PL II., fig. 6) are much 

 modified, being thin and flexible. Each 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 (PL II. , fig. 7) are closely approxi- 

 mated on their inner sides and joined at the base, so that 



