41 8 Proceedings of the Boi/al Irish Academy. 



Geographical Distribution of the Species noted above. 



The preceding table indicates broadly the known geographical range of 

 the species recorded above. A study of this table reveals the interesting 

 fact that the marine fauna of the west of Ireland, as far as these orders 

 of Crustacea are concerned, is a blending of northern forms with southern 

 species from the Mediterranean, the latter element somewhat preponderating. 

 The single species of Nebalia, N. hvpes, extends from Norway to the Medi- 

 terranean. Among the Cumacea we find seven species have been recorded 

 from Norway and ten from the Mediterranean, while five are common to 

 Norway, the British area, and the Mediterranean. Five species, Nannastacus 

 itnguiculahis, Eudorella truncatula, Bodotria pulchella, Cumopsis goodsiri and 

 Vauntompsonia cristata, have the northern limit of their geographical range 

 in the British area, while two forms, Psatdocuma similis and Diastylis rostrata, 

 have yet to be met with south of the British area. One species, Nannastacus 

 brevicaudatus, is peculiar to the Clare Island marine area, Diastylis spinosa 

 has so far only been found in the British area, and none of the species 

 extend to the American coasts. 



Of the three species of Euphausiacea, one, Meganyctiphanes norvegica, 

 extends from Norway to the Mediterranean ; the second, Nyctiplianes couchi, 

 is known from the Mediterranean, but not from Norway; while the third, 

 Thysanoessa inermis, is not certainly known to the south of Britain. 

 M. norvegica is also found off the North American coast. Here again, 

 therefore, we get a blending of northern and Mediterranean species. 



Of the nineteen species of Mysidae here recorded, thirteen extend to the 

 Mediterranean and eleven to Norway, but only five from Norway to the 

 Mediterranean. Six of them have the southern limit of their known 

 geographical range in the British area, while eight of them have not yet been 

 recorded south of the English Channel. There are no species peculiar to the 

 British area, and only one species, Hetcromysis formosa, extends to the 

 American coasts. No Stomatopoda are known from Norway, so that the 

 Sto'matopod element in the fauna of the West of Ireland is of southern 



