26 BRITISH OOPEPODA. 



bears two apical and two marginal setae ; the last joint 

 of the main limb is armed with several spine-like setae 

 at the apex and on the outer margin, and the basal 

 joint has one strong plumose seta. Mandible (fig. 5) 

 broad and strongly toothed at the extremity; basal 

 joint of the palp large. The maxilla (fig. 6) consists 

 of a small masticatory segment, and a 4-digitate palp, 

 the extremities of all the digits bearing three or four 

 long setae. The anterior foot-jaw (fig. 7) has three 

 marginal digits ; the posterior (fig. 8) is 3-jointed, 

 first and second joints subequal, third small, slender, 

 and having three apical setae, one of which is longer 

 than the others and forms a slender claw ; the basal 

 joint has four marginal setae, two attached at the apex 

 being very long ; the second joint has a series of about 

 eight setae on its inner margin. The inner branch of 

 the first pair of feet (fig. 9) is rather longer than the 

 outer branch, the terminal joints in both cases being 

 rather long and slender ; the outer margins are fringed 

 with spine-like setae, those at the apex of each joint on 

 the outer branch being unusually large. The basal 

 portion of the limb is armed with three strong spines 

 (fig. 9, a, a, a), the innermost of which is broad and 

 lancet-shaped ; the second, third, and fourth pairs of 

 feet are somewhat similar, but their setose armature is 

 not quite so strong; in the male the third joint of the 

 inner branch in the second pair (fig. 11) is converted 

 into two spine-like processes and two slender setae, 

 while the setae usually present on the inner margins of 

 the first and second joints are quite rudimentary. The 

 fifth foot (figs. 12, 13) is composed of two joints fringed 



