ARPACTICUS. 
215 
distinct from each other. The thorax is composed of four 
segments, and is large and rounded. The abdomen con- 
sists of six slender segments, the last being bilobed, and 
giving off two long setae and two short ones. The whole 
animal is beautifully coloured with green, red, and purple. 
The eye is large, of a ruby colour. 
The antennae (t. XXVIII, f. 2 a) are short, divided into 
seven articulations, all of which are setiferous. The first two 
are short and stout ; the third is much longer, toothed on 
its upper edge, and giving off at its extremity several long 
setae. The last four are small and short. 
The 4, antennules (f. 2 b) are composed of two seg- 
ments, the first giving off a shoot from about the middle 
of its length, and the second terminating in several stout 
setae. 
The mandibles and anterior or first pair of foot-jaws 
are strong, and resemble the same organs in Cyclops 
quadricornis . The posterior foot-jaws (f. 2 d) are shorter, 
but much stouter than those of the preceding species, 
and consist, as in them, of the two joints and strong 
terminal hooked claw. The thoracic pair of feet (f. 2 e) 
differs in structure from the others. It consists of two 
stalks, rising from a common base ; the anterior or upper 
stalk composed of one long joint and a very short one, 
which terminates in a strong claw, the posterior or in- 
ferior stalk being very short, toothed on its edge, and 
giving off several stout setae. The abdominal feet re- 
semble those of preceding species, the setae with which 
they and the fulcra are provided being all plumose. The 
fulcra (f. 2 c) resemble those of chelifer. The setae of the 
caudal segment, however, are not plumose. 
This species is at least three times larger than the pre- 
ceding, and the body is stouter and more rounded. 
Hab . — Along with preceding in Berwick Bay, 1835. 
Dover, North Foreland, September 1849. 
