890 THE VOYAGE OF H.M.S. CHALLENGED. 



1882. Iphimedia, Haswell, Catal. Australian Crust., p. 241. 



1882. „ Sars, Oversigt af Norges Crustaeeer, p. 100. 



1883. „ Stebbing, Ann. and Mag. Nat. Hist., ser. 5, vol. xi. p. 206. 



1885. „ Carus, Prodr. Fauna? Mediterranean, p. 406. 



1886. „ Gerstaecker, Bronn's Klaasen und Ordnungen, Bd. v. Abtb. ii. p. 504. 

 1886. Panoplaa (pars), Thomson and Chilton, Critical List Crust. New Zealand, p. 150. 



For the original definition of the genus, see Note on Bathke, 1843 (p. 204). For 

 Kr0yer's definition of Microcheles, see Note on Kr0yer, 184G (p. 216), and for Thomson's 

 definition of Panoplcca, see Note on Thomson, 1880 (p. 524). Boeck defines the genus 

 as follows : — 



" Upper Lip not much elongated, broad, apically insinuate. 



"■Mandibles a little shorter and broader than in the genus Vertumnus [Acanthonoto- 

 zomct]. 



" First Maxillag with the palp two-jointed, the first joint short ; the inner plate 

 smaller than in the preceding genus [_Acanthonotozoma~\. 



" Maxilli peels with the last joint of the palp wanting. 



" First and Second Gnathopocls slender, but furnished with a very narrow, cheliform 

 band. 



" Body thick, yet deep ; with the side-plates large, rigid." 



In the definition of the compared genus, Acanthonotozomct , Boeck does not mention 

 the mandibles ; of the first maxdlse he says, " inner plate very large, triangular, furnished 

 with many plumose setae." 



Iphimedia pacifica, Stebbing (PL LXXL). 



1883. Iphimedia pacifica, Stebbing, Ann. and Mag. Nat. Hist., ser. 5, vol. xi. p. 207. 



The Head almost concealed ; the long rostrum, curving slightly downwards, reaches 

 nearly to the end of the first joint of the upper antennae ; the lateral margins of the head 

 below the upper antennae form two sharp processes, of which the lower is rather the 

 larger; the first segment of the peraeon curves over the head and is dorsally longer than 

 any one of the five following segments, but much shorter than the seventh segment ; 

 each has the postero-lateral angles acute, forming backward-directed processes, more and 

 more developed in each successive segment, in the last three, and especially in the last, 

 the process becoming prominent and directed a little outwards as well as backwards ; in 

 the last peraeon-segment and in each of the first two of the pleon there is a pair of large 

 dorsal backward-directed teeth or processes ; the first three pleon-segments have an 

 inchoate dorsal carina, the postero-lateral angles produced into an acute upturned tooth, 

 and the hinder margins likewise produced into a sharp tooth near the centre, this tooth 

 in the third segment being longer than the lower tooth and curved upwards at the point ; 

 dorsally, the hind margin of the third segment forms a small lobe on either side ; the 



