AiMPIIlPODA — STEBBING. 585 



In the recent definition the maxillipeds are considered to agree 

 \vith those of Panoploea, Thomson, and they sometimes do, but 

 in /. pulchridentata oi the Challenger Expedition, tlie second joint 

 of the palp is an exception, not being produced along the inner 

 margin of the third, as it is in Panoploea, Pariphimedia, and 

 some species of Iphimedia, among them being /. discreta, sp.nov. 

 That species, however, in the slenderness of its mandibular palp 

 agrees less with its own genus and the other two just mentioned 

 than it does with Odius. Such interlacing of characters may at 

 least be regarded as some indication that the family is a natural 

 one. 



In 1906, Walker added three large antarctic species to the 

 genus, /. echinuia, I. longipes, and the densely spinose /. 

 hodgsoni. 



IPHIMEDIA AMBIGUA, Hasioell 



Iphimedia C?) ambigua, Haswell, Proc. Linn. Soc. N. S.Wales, iv., 

 1880, p. .327, pi. xxiv., figs. 2, 2a.-. 



Iphimedia (?) ambigua, Haswell, Austr. Mus. Cat. v., Crust., 1882, 



p. 241. 

 Pa7ioploea ambigua, Stebbing, Das Tierreich, xxi., 1906, p. 213 



(without description). 



Head with long pointed rostrum. First and seventh peraeon 

 segments much longer than any of the intervening five. Seventh 

 peraeon segment and first to third pleon segments dorsall}'^ pro- 

 duced into a pair of strong teeth. First to fourth side-plates suc- 

 cessively deeper, the fourth emarginate above, in the figure x'ounded 

 below, the fifth to the seventh each with a tooth-like postero-lateral 

 angle, the first three pleon segments being similarly provided, the 

 tooth strong only in the third segment, and there surmounted 

 by a larger upturned tooth midway between the lower angle and 

 the dorsal tooth. Eyes, in figure, rounded oval. First anteunse 

 rather shorter than second antennae, the first joint rather large. 

 First gnathopod slender, filiform. Second gnathopod slender, 

 subchelate. Third peraeopod with second joint produced above 

 into an acute tooth, fourth peraeopod with small tooth on this joint 

 above and below, fifth peraeopod with hind margin serrate and 

 lower angle produced into a tooth. Third uropod with inner 

 ramus longer than the outer, two-jointed. Telson scale-like, entire, 

 the detail figure 2x representing it in dorsal view as oval, without 

 the least trace of emargination. 



By the last character this .species is distinguished from all 

 other known species of Iphimedia, and agrees only with Pariphi- 

 media inteyricauda, Chevreux. Its position in the family remains 

 aml)i"U0us, so long as the mouth organs continue unknown, but 



