10 BRITISH PARASITIC COPEPODA. 



with the exception of Chondr acanthus are of a some- 

 what similar type to that of Lepeophtheirus. The first 

 maxillae are one-jointed and are situated near the 

 lateral margins, slightly posterior to the base of the 

 antennae. The second maxillae are also one-jointed and 

 are placed at the sides of the suctorial tube which 

 carries the mouth at its apex. The first maxillipeds 

 consist of two-jointed appendages and are situated just 

 behind the second pair of maxillae. The apical joint is 

 claw-like and prehensile. The second pair arise mid- 

 way between the first and the first pair of feet. They 

 are composed of two joints. The basal joint is much 

 inflated, and the apical is in the form of a powerful 

 claw which closes upon the basal joint and provides 

 the animal with a strong grasping appendage. The 

 first three pairs of feet consist of an endopodite and an 

 exopodite attached to a two-jointed protopodite. The 

 endopodite of the first pair is rudimentary and is 

 represented by a minute joint bearing a few setae. 

 The exopodite is two-jointed. In the second pair both 

 the endopodite and the exopodite are three- jointed. 

 The protopodite of the third pair is greatly developed 

 and forms a prominent lamella. The exopodite and 

 endopodite are very small, the former being com- 

 posed of two and the latter of three joints. Each of 

 the first three pairs of feet is attached to a sternal 

 plate. The protopodite of the fourth pair of feet is 

 two-jointed and the exopodite is also two-jointed, but 

 there is no trace of an endopodite. A strong chitinous 

 plate with a bifid apex arises from the middle line 

 between the second pair of maxillipeds. This is 

 known as the sternal fork. Its function is not clearly 

 established. It has been suggested that it acts as a 

 crutch to raise the body of the animal from that of the 



