426 EEV. T. R. E. STEBBING ON AMPHIPODA FKOM 



Paraceradocus, n. g. 



Side-plates not deep, the first larger than the fourth. Eirst antennte longer, but not 

 stouter than the second, and with shorter peduncle. Upper lip transversely elliptic. 

 Under lip with principal lobes dehiscent. Palp of mandibles elongate ; third joint not 

 short. First maxillge with large inner plate, carrying setae only on the apex ; the palp 

 broad. Second masilloe having tlie inner plate fringed along inner margin. Limbs of 

 perseon, uropods, and telson as in Ceradocns. 



The type-species is Faraceradociis IliersU (Pfeffer), 1888, from South Georgia. 



Gen. Ceradocus Costa, 1853. 



The species belonging to this genus are : — 1. Ceradocus orchestiipes A. Costa, 1853, 



which includes the preoccupied Gammarus fasciatus O. G. Costa, 1844 ; 2. Ceradocus 



Torelli (Goes), 1866 ; 3. Ceradocus ruhro-macidatus (Stimpson), 1856 ; 4. Ceradocus 



semiserratus (Bate), 1862 ; of which the first and last are both named Ceradocus 



fasciatus by Professor Delia Valle. 



Gen. Maera Leach, 1814. 



In this genus I propose the name Ilaera Westwoodi for Gammarus Kroyeri Bell and 

 Westwood, 1855, Avhicli is distinct from the earlier Gammarus Kroyeri Rathke, 1843, 

 and add to tlie accepted species Ilaswell's Megamoera 3Iastersii, 1880; Dana's Gam- 

 marus asper, 1852 ; his Gammarus ? indicus, 1853 ; Gerstfeldt's Gammarus kilrgeusis, 

 1858 ; and Dana's Amphithoe puhescens, 1852. The last four are involved in some 

 obscurity. 



Gen. ElasmopUvS A. Costa, 1853. 



To the sjiecies already accepted in this genus may be added Haswell's Megamoera 

 suensis, 1880 ; his Iloera viridis, 1880 ; his Megamoera Boeckii, 1880 ; the Moera crassi' 

 mana of Miers, 1884, the specific name becoming crassimanus ; and the Maera Miersi of 

 Wrzesniowski, 1879. The last two are rather obscure. 



Plesiogammarus, n. g. 



Near to Gammarus. Many of the segments have a marginal swelling. The pleon 

 carries dorsal setae, but no dorsal spines. Peduncle of first antennae longer than that of 

 second. Third to fifth peraeopods with the second joint long and narrow. First uropods 

 reaching to the end of the short third pair. Telson not cleft to the base. 



The type-species is Plesiogammarus Gerstaeckeri (Dybowsky), 1874, from Lake 

 Baikal. 



