20 U.S. NIATIONAIj museum bulletin 271 



Antarctic: Oediceroides, Pseudorchomene*, Tryphosites*, Uristes. 



Antiboreal: Acontiostoma*, Amaryllis, Heterophoxus. 



Tropical: Idunella, Platyischnopus. 



Warm-temperate: Listriella. 



Arctic-boreal: Anonyx, Bathyporeia, Dulichia, flock of haustoriid genera, 



Lepidepecreum Monoculodes, Oediceros, Onisimus, Paramphithoe, Pontocrates, 



Pseudalibrotus, Westwoodilla, Unciola. 



The dominant genera of Gammaridea in epif aunas of intertidal and 

 shallow sublittoral (0-75 m) zones by gross region (*= genera with 

 low specific diversity but high individual frequency; N=nestler; 

 I=inquLline; D = domicolous tube-dweller). 



Cosmopolitan : Allorchestes N, Ampithoe D, Cerapus D, Colomastix I, Corophium 

 D, Ericthonius D, Gammaropsis D, Hyale N, Jassa D, Lembos D, Leucothoe 

 I, Maera N, Melita N, Photis D, Podocerus D, Polycheria I, Sienothoe I. 



Bipolar, cold-water: Aora D, Apherusa N, Halirages N, Liljeborgia N, 

 Paramoera N, Pontogeneia N, Proboloides (Metopoides) N. 



Antarctic-antiboreal: Amaryllis, Andaniotes ?I, Atyloella N, Atylopsis N, 

 Bovallia N*, D jerboa N*, Echiniphimedia, Gnathiphimedia, Haplocheira T>, 

 Oradarea, Paradexamine, Pariphimediella, Pontogeniella N, Seba I, Schraderia 

 N*, Stebbingia N*, Thaumatelson I. 



Warm-temperate and tropical: Amphilochus, Anamixis I*, Batea N, Ceradocus 

 N, Cheiriphotis D*, Chevalia D*, Cymadusa D, Elasmopus N, Gitanopsis, 

 Grandidierella D, Leucothoides I*, Microdeutopus D, Microjassa D, Paragrubia 

 D*, Parelasmopus N, Parhyale N*. 



Arctic-boreal: Amphilochus, Anisogammarus N, Aoroides D*, Atylus N, 

 Calliopius N, Cressa, Gammarus N, Gammarellus N, Gitanopsis, IschyrocerusD, 

 Leptocheirus D, Metopa, Metopella, Microdeutopus D, Neopleustes N, Para- 

 pleustes ^jPleustes N, Sym,pleustes N. 



The dominant genera of Gammaridea in the pelagic realms, in- 

 cluding some demersal genera, are as follows (* = dominant by 

 frequency of individuals only). 



Neritic: Megaluropus, Paraphoxus (males), Synchelidium (pelagic phases), 



Epipelagic: Stenopleura*, Synopia. 



Bathy- and abyssopelagic: Andaniexis, Astyra, Cleonardo, Cyclocaris*, 

 Cyphocaris, Euandania*, Euonyx, Eusirella, Eusirogenes* , Eusirus, Halice, 

 Hirondellea, Hyperiopsis, Ichnopus, Joubinella, Koroga*, Metacyphocaris*, 

 Orchomene, Paracallisoma* , Paralicella, Parandania*, Parargissa, Phippsiella, 

 Rhachotropis, Scopelocheirus. 



The dominant genera of bathyal-abyssal benthos are as follows 

 (* = dominant by frequency of individuals only. D = demersal?). 

 Conservative numbers of species in depths exceeding 200 meters 

 are given following each genus. 



Benthic: Amathillopsis 6, Ampelisca 25, Anonyx 5 (Pacific boreal), Bathy- 

 amaryllis 4, Byblis 5, Bonnierella 5, Bathymedon 4, Bruzelia 4, Dulichia 6 

 (Atlantic boreal), Epimeria 6, Haploops 8, Harpinia 4 (Atlantic boreal), 

 Harpiniopsis 19, "Hippomedon" 12, Lepidepecreum 6, Leucothoe 4, Liljeborgia 



