42 22 Proceedings of the Royal Irish Academy. 



Geographical Distribution of the Species noted above. 



The list of Clare Island Ampkipoda includes ninety-five species, of which 

 seventy-nine are known from the coasts of Norway and forty-five from the 

 Mediterranean, while thirty-nine are common to all three places. Thirty-three 

 of the species are Arctic forms, of which fourteen extend to the Mediterranean, 

 the remaining nineteen having not yet been recorded from further south than 

 the coasts of France. 



Of the non- Arctic species, twenty five extend from Norway to the 

 Mediterranean, and a further twenty-one are known from the Atlantic coasts 

 of Europe from Norway to France, but have so far not been met with in the 

 Mediterranean. 



The following six species : — Metaphoxus fultoni, Colomastio; pusilla, Guemea 

 coalita, Microdeutopus danmoniensis, Isaea montagui, and Jassa ocius, are 

 Mediterranean forms which have the northern limit of their distribution in 

 the waters of the British Isles, and do not reach Norway. 



The following ten species have the centre of their distribution in British 

 waters, and are not at present known from either Norway or the 

 Mediterranean : — 



Lysianassa ceratinus Urothoe elegans. 



Socarnes erythrophthalmus. Ceradocus semiserratus. 



Metaphoxus pectinatus. Maera tenuimana. 



Urothoe marinus. Coremepas versiculatus. 



Urothoe brevieomis. Caprella fretensis. 



Finally seventeen of the species are known from the coasts of North 

 America : 



Hoplonyx cicada. Amphithoe rubrieata. 



Leucothoe spinicarpa. Ischyrocerus anguipes. 



Ampelisca spinipes. Erichthonius brasiliensis. 



Calliopius rathkii. Siphonoecetes colletti. 



Gamrnarellus homari. Proto ventricosa. 



Gammarus loeusta. Caprella linearis. 



Gammarus marinus. Hyperia galba. 



Dexamine thea. Euthemisto compressa. 

 Microdeutopus danmoniensis. 



All but five of these species — Gammarus marinus, Microdeutopus 

 danmoniensis, Amphithoe rubrieata, Erichthonius brasiliensis, and Siphonoecetes 

 colletti — are Arctic species. 



