42 R. NORRIS WOLFENDEN. 



Posterior foot jaws with segments proportionately Bl, B'2, Ri = 9, 8, 9. Ri 

 elongated and thin, with five distinct segments. 



First feet, Ri of one, Re of three segments, the first without Se ; Ri with four Si. 



Second feet, Ri of two, Re of three segments ; no Si on B 1 or B 2. 



Fourth feet, Ri and Re of three segments each. The end saw extremely long, and 

 longer than the whole Re, broad and coarsely serrated marginally. 



In the second to the fourth feet the Re 3 has three outer marginal spines. No 

 fifth feet. 



The few males present were apparently immature. 



HALOPTILUS (GIESBRECHT). 



One species of this genus appears to be characteristic of the Antarctic fauna, since 

 it is present in very many of the ' Gauss ' samples, but curiously enough, occurred only 

 once in the ' Discovery ' collection. It is large, and distinguished at a glance from any 

 other examples of the genus by the prominent black ocellus dorsally placed, an organ 

 not possessed by any other species of Haloptilus. 



HALOPTILUS OCELLATUS. 

 (Plate III., figs. 1, 2.) 

 Haloptilus ocellatus, Wolfenden, Plankton Studies, Part I. (1905), p. 14. 



9, of length, from the end of the frontal spine to the end of the furca, 875 mm., 

 with cephalothorax over five times as long as the abdomen ; the conjoined head and 

 first segment much longer than the remaining segments of the anterior body (about 

 one- third) ; the last two segments of the cephalothorax united, and with rounded 

 margins. On the second segment, in the centre of the dorsum, or a little to the right 

 of the centre, is a prominent and very black rounded pigmented ocellus, standing out 

 in clear contrast to the rest of the very transparent animal. The frontal spine is long, 

 tapering, and usually a little curved downward, and often laterally, towards the tip. 

 The distance from the tip of the spine to the base of the anterior antennae is equal to 

 the distance between the latter and nearly to the distal end of the second cephalic 

 segment. Abdomen of four segments, with the anal as long as the two preceding, and 

 the furcal segments over twice as long as broad. 



Anterior antennae a little longer than the whole animal, reaching beyond the furca 

 by about three or four joints, and sparingly setiferous. 



Posterior antennae with endopodite very long and exopodite very short, the latter 

 of six joints, with doubtful division of the last, which would be the seventh joint, the 

 basal or first segment very long, and nearly as long as the joints distal to it. lie not 



