Introduction.......................................................................................................................page 13 Key to fresh and brackish water amphipods........................................................................... 21 Key to marine and brackish water amphipods........................................................................ 30 Taxonomical part Gammaridea-species Lysianassidae Dana, 1849 Hippomedon denticulatus (Bate, 1857)...................................................................................... 42 Lepidepecreum longicornis (Bate & Westwood, 1862).............................................................. 46 Orchomene humilis (Costa, 1853)............................................................................................... 49 Orchomenella minuta (Kr0yer, 1846).......................................................................................... 50 Socarnes vahlii (Kr0yer, 1838).................................................................................................... 54 Tryphosa nana (Kr0yer, 1846)......................................................................................................58 Tryphosella sarsi Bonnier, 1893...................................................................................................62 Tryphosites longipes (Bate & Westwood, 1861).........................................................................63 Aristiidae Lowry & Stoddart, 1997 Aristias neglectus Hansen, 1888..................................................................................................67 Perrierella audouiniana (Bate, 1857)......................................................................................... 68 Uristidae Hurley, 1963___________________________________________________________ Menigratopsis svennilssoni Dahl, 1945....................................................................................... 70 Onisimus edwardsii (Kr0yer, 1846)............................................................................................. 74 Tmetonyx acutus (5a rs, 1891)............................................................................. 75 Tmetonyx cicada (Fabricius, 1780).............................................................................................. 76 Tmetonyx similis (5a rs, 1891).......................................................................................................79 Scopelocheiridae Lowry & Stoddart, 1997 Scopelocheirus hopei (Costa, 1851)............................................................................................. 80 Ampeliscidae Krpyer, 1842 Ampelisca brevicornis (Costa, 1853)........................................................................................... 85 Ampelisca diadema (Costa, 1853)............................................................................................... 89 Ampelisca gibba 5a rs, 1883..........................................................................................................92 Ampelisca macrocephala Liljeborg, 1852....................................................................................93 Ampelisca spinipes Boeck, 1861.................................................................................................. 97 Ampelisca tenuicornis Liljeborg, 1855......................................................................................... 98 Ampelisca typica (Bate, 1856)................................................................................................. 102 Byblis abyssi Sars, 1879 ........................................................................................................... 106 Byblis gaimardii (Kr0yer, 1846)................................................................................................ 107 Haploops tenuis Kanneworff, 1966.......................................................................................... 110 Haploops tubicola Liljeborg, 1855............................................................................................ 114 Iphimediidae Boeck, 1871 Iphimedia minuta G.O. Sars, 1882............................................................................................ 119 Iphimedia obesa Rathke, 1843................................................................................................. 123 Acidostomatidae Stoddart & Lowry, 2012 Acidostoma laticornis G.O. Sars, 1879...................................................................................... 128 Acidostoma obesum (Bate, 1862)............................................................................................ 129 Stegocephalidae Dana, 1855 Andaniopsis nordlandica (Boeck, 1871).................................................................................... 133 Lafystiidae Sars, 1893 Lafystius sturionis Kr0yer, 1842................................................................................................ 134 Amphilochidae Boeck, 1871 Amphilochoides serratipes (Norman, 1869)................................................................... page 139 Amphilochus manudens Bate, 1862......................................................................................... 142 Gitana sarsi Boeck, 1871............................................................................................................146 Paramphilochoides intermedius (Scott, 1896)........................................................................ 150 Paramphilochoides odontonyx (Boeck, 1871)...........................................................................151 Leucothoidae Dana, 1852 Leucothoe incisa Robertson, 1892............................................................................................ 155 Leucothoe lilljeborgi Boeck, 1861.............................................................................................. 158 Leucothoe spinicarpa (Abildgaard, 1789)................................................................................ 162 Stenothoidae Boeck, 1871 Hardametopa nasuta (Boeck, 1871)......................................................................................... 167 Metopa alderi (Bate, 1857)...................................................................................................... 171 Metopa borealis Sars, 1882...................................................................................................... 175 Metopa pusilla Sars, 1892..........................................................................................................178 Stenothoe monoculoides (Montagu, 1815)...............................................................................182 Stenula rubrovittata (Sars, 1883)............................................................................................. 186 Stenula solsbergi (Schneider, 1884)......................................................................................... 190 Cressidae Stebbing, 1899 Cressa dubia (Bate, 1857)......................................................................................................... 193 Haustoriidae Stebbing, 1906 Haustorius arenarius (Slabber, 1769)....................................................................................... 197 Pontoporeiidae Dana, 1852 Monoporeia affinis (Lindström, 1855)......................................................................................201 Pontoporeia femorata Kröyer, 1842.........................................................................................205 Urothoidae Bousfield, 1978 Urothoe brevicornis Bate, 1862................................................................................................ 209 Urothoe elegans (Bate, 1857)................................................................................................. 210 Urothoe grimaldii Chevreux, 1895............................................................................................214 Urothoe poseidonis Reibisch, 1905...........................................................................................215 Argissidae Walker, 1904 Argissa hamatipes (Norman, 1869)..........................................................................................219 Oedicerotidae Lilljeborg, 1865 Arrhis phyllonyx (Sars, 1858).................................................................................................... 225 Bathymedon longimanus (Boeck, 1871)...................................................................................226 Deflexilodes norvegicus (Boeck, 1871)......................................................................................227 Deflexilodes subnudus (Norman, 1889).................................... 230 Deflexilodes tenuirostratus (Boeck, 1871) ...............................................................................232 Halicreion aequicornis (Norman, 1869)....................................................................................233 Kroyera carinata Bate, 1857...................................................................................................... 234 Monoculodes packardi Boeck, 1871.........................................................................................235 Monoculopsis longicornis (Boeck, 1871)...................................................................................239 Pacifoculodes pallidus (Sars, 1892)........................................................................................... 240 Perioculodes longimanus (Bate & Westwood, 1868)..............................................................