132 Proceedings of ihe Royal Irish Academy. 



latitude on the so-uth. and the 100 fms. line on the west. The deep- 

 water district is practically confined to the western coasts and 

 comprises the area contained between the 100 fathoms and the 1000 

 fathoms lines and the parallels of latitude 56° and 49° 30'. Por the 

 conyenience of students of geographical distribution the known range 

 of the species round the coast of Ireland has been divided iato the 

 same six provinces which I adopted in the paper on the Marine 

 MoUusca of Ireland (Proc. Eoy. Ir. Academy (3) vol. v., pp. 477-662, 

 1900). 



These provinces are — 



i. ISTorth-east. From Malin Head, Co. Donegal to St. John's Point, 



Co. Down, 

 ii. East. Prom St. John's Point to Camsore Point, Co. "\\''ex- 



ford. 

 iii. South. Prom Camsore Point to Cape Clear, Co. Cork, 

 iv. South-west. From Cape Clear to Loop Head, Co. Clare. 

 T. TTest. From Loop Head to Erris Head, Co. Mayo, 

 vi. Xorth-west. From Erris Head to Malin Head. 



The names of the species which have not been found at a less 

 depth than 100 fms. off the Irish coast are placed within square 

 hrackeU and can thus be readily distinguished. "Whenever a species 

 is found in shallow-water in some and only in deep-water in other 

 provinces, then the numbers denoting these latter provinces are included 

 in square brackets. 



I have followed the classification, and with one or two exceptions,, 

 the nomenclatui'e adopted by Bell in the " Catalogue of the Eritish 

 Echinoderms in the British Museum," 1892 ; but for the convenience 

 of reference I have given the names used by Forbes in his " History of 

 British Stai-fishes " whenever these names differ from those of the 

 British Museum catalogue. 



The general distribution of each species is given veiy briefly, and has 

 been derived principally from the "Challenger" Reports and the writings 

 of Agassiz, Bell, Carus, Hoyle, Ludwig, Lyman, jSTorman, Yenill, &:c. 



The total nujnber of species of Echinoderms found in the seas 

 surrounding the British Islands is 134, and the number in this list 

 is 87, so that the Irish Fauna includes nearly two-thmls. If we 

 exclude fi-om the Irish list the deep-water forms which belong perhaps 

 more strictly to the general Atlantic Fauna, and confine the British list 

 to the species which have been found at less than 100 fms. depth on 



