MARINE GAMMARIDEAN AMPHIPODA 291 



Paraleiicothoe Stebbing 



Paraleucothoe Stebbing, 1899d.— Stebbing, 1906. 



Type-species: Leucothoe novaehollandiae Haswell, 1880c (original 

 designation). 



Coxa 2 at least as long as broad, rounded ventrally and anteriorly, 

 coxa 1 not concealed; mandibular palp 3-articulate; outer plate of 

 maxilliped reaching almost to end of palp article 1. Species: ], 

 Australia, littoral. 



Liljeborgiidae 



Figures 115, 116 



Diagnosis. — Molar of mandible poorly developed, not triturative, 

 accessory flagellum 2- or more articulate. See Gammaridae, Eusiridae, 

 Pleustidae, Haustoriidae, Astyridae, Vitjazianidae. 



Description. — Accessory flagellum always present, 2- or more 

 articulate; rostrum inconspicuous; coxae long or of medium length; 

 upper lip possibly slightly emarginate, not conspicuously so; mandibles 

 always bearing 3-articulate palp with article 1 often elongate and as 

 long as article 3 (except Idunella forming a link to Gammaridae); 

 molar of mandible obsolescent, nontriturative; remaining mouthparts 

 basic; gnathopods powerfully subchelate; uropod 3 with flattened, 

 lanceolate rami; telson deeply cleft, not greatly elongate, apices of 

 lobes bifid. 



Relationship. — In the Gammaridae only the genus Parelasmopus 

 has an elongate mandibular palp article 1 but its mandibular molar 

 has a Avell-developed grinding surface, unhke that of Liljeborgiidae. 

 Apart from the mandible the Liljeborgiidae are like the Gammaridae. 



The Astyridae differ from the Liljeborgiidae by the overall appear- 

 ance and the presence of inner lobes or a broad medial space on the 

 lower hp (see figures 32 and 41). Astyrids have feeble gnathopods, 

 whereas those of liljeborgiids are i)owerfully develoi)ed. The rami of 

 uropod 3 of Astyridae are much more elongate than those of Lilje- 

 borgiidae. 



Some genera of Pleustidae have poorly developed mandibvdar 

 molars as in Liljeborgiidae and the lower lips are similar. Pleustids, 

 however, have vestigial or no accessory flagella and usually hav^e 

 uncleft telsons, but one s})ecies of Austropleustes confounds the defini- 

 tion. See Gammaridean Family Key G for specific distinctions. 



The Eusiridae always have the accessory flagellum 2-articulate or 

 less and this conflicts only with the genus Listriella in the Liljeborgiidae. 

 But in contrast to the Eusiridae, Listriella usually has a 2-articulate 



