CRUSTACEA FROM THE FALKLAND ISLANDS. 359 



1910. Pariphimedia Stebbing, Mem. Australian Mus. vol. iv. 



pt. 2, p. 584. 

 1912. „ Chilton, Tr. Roy. Soc. Edinb. vol. xlviii. 



p. 487. 



H. Ilathke's Iphimedia and G. M. Thomson's Panoplma, 

 according to Chevreux, are distinguished from this genus chiefly 

 by the following characters : — the cutting-edge of the mandibles 

 not denticulate, the principal lobes of the lower lip emarginate 

 on the inner edge, the palp of the first maxillae two-jointed, the 

 inner lobe of the second maxillfe carrying a single sei-ies of 

 setae, the second gnathopod not completely chelate, and the 

 telson apically emarginate. 



It would, 1 think, be inconvenient to press the first of these 

 characters as essential to either of the genera mentioned ; but 

 ])oth are i-ather sharply separated from Pariphimedia by the two- 

 jointed palp of the first maxilla, in strong contrast with the feeble 

 single-jointed structure in Chevreux's genus, which makes an 

 approach to that foinid in Odius Lilljeborg. 



In adding a second species to the genus, I feel fairly sure that 

 it is identical with the scantily-described Iphimedia norviani 

 Cunningham, which lias so long remained oljscure. But the 

 addition tends to weaken the original definition, inasmuch as the 

 telson has a neat little convex emargination which helps to dis- 

 tinguish it from P. integricauda, in which, as the specific name 

 declares, the telson is unincised. By a curious contrariety the 

 upper lip, which is there slightly emarginate, is here simply 

 convex. The mandibles in the two species essentially agree, the 

 trunk tapering to a fine point, the distal part of the margin 

 minutely denticulate, the molar represented by a projection with 

 no triturating surface, the palp well developed, its second joint 

 much the longest, the third curved, setose. Neither mandible in 

 P. normani has a secondary plate, so far confirming the sugges- 

 tion which I have earlier made, that the same is the case in 

 P. integricauda. While it may be said that the distal lobes of 

 the lower lip are in both species undivided-, it will be seen that in 

 P. nonaani there is a marked tendency towards apical division. 



Pariphimedia normani (Cunningham). (Pis. IV. & Y.) 



1871. Iphimedia normani Cunningham, Tr. Linn. Soc. London, 



vol. xxvii. p. 498, pi. 59. fig. 7. 

 1 906. „ „ Stebbing, Das Tierreich, vol. xxi. p. 2 1 7. 



This species, by the notable features of its mouth-organs and 

 gnathopods, clearly belongs to the family Acantiionotozomatidae. 

 But of spine-like processes on the back, which so many members 

 of that family exhibit, it is singularly devoid. Only tne third 

 segment of the pleon makes a show of relationship in this respect 

 by an upturned postero-lateral angle and high up on the side 

 a still stronger upturned tooth. The two preceding segments 

 have the postero-lateral. angle produced into acute points, and 



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