510 W. WILLIAMSON AND C. D. SOAR ON BRITISH HYDRACARINA : 



to be found. The second and third segments of the palpi show 

 the usual groups of fine pores, but in the fourth segment these 

 gradually disappear towards its distal extremity. 



The capitulum is of normal form, but rather small, as it does 

 not quite take up the bay formed by the first pair of epimera. 

 The posterior processes are short and thick. The mandibles 

 are slender in structure, and about a quarter of a millimetre 

 in length. 



The palpi are about 0'4 mm. in length, and more slender than 

 the first pair of legs. The fourth segment is distinctly longer 

 than the third, and not quite so stout. The first segment has 

 only one fine bristle on its extensor surface. The second 

 segment is porose, and has four or five short bristles on its 

 extensor surface. The characteristic bristle on the flexor surface 

 is nearly straight and very slightly pectinate. It stands 

 distinctly back from the distal edge. The third segment is 

 also porose, and carries the characteristic of the sub-genus, 

 namely, six long bristles on the inner surface of the segment. 

 Of the three which are almost distal, two are close to the 

 extensor surface. The fourth is not quite proximal, and is close 

 to the extensor surface also. The remaining two are just a 

 little posterior to the middle line one is at the extensor surface 

 and the other just inside of it. All the bristles are very long, 

 some going beyond the distal end of the fourth segment. The 

 fourth segment is weakly porose, and it should be noted that the 

 two fine pores on the flexor surface are very close to one another 

 and the accompanying hairs are very short. The rest of the fine 

 hairs are grouped distally. The fifth segment is very short 

 and tapered. 



The epimera are of unusual size and possess an extension laterally 

 and posteriorly which forms quite a characteristic feature, and is 

 apparently most marked in the male. The fourth pair of epimera 

 are so large as to include within the posterior margin the gland 

 pore usually found outside. The articulation of the fourth pair 

 of legs also lies well back from the lateral margin. The lateral 

 expansion sometimes draws so far forward as to come close up to 

 the second epimera. Just behind the third pair of legs, the 

 expansion of the epimera encloses a large gland pore. The posterior 

 inner edge of the fourth pair is nearly straight, making the 

 corner almost right-angled. At each corner a short hair will be 



