FROM THE EDDYSTONE GROUNDS TO START POINT. 519 



Differences of this kind are of very great interest, but our knowledge of 

 them is far too slight at the present time to make any satisfactory 

 explanation possible. 



In the Presidential Address to the Biological Section of the British 

 Association, at the Ipswich meeting, Herdman gives a list of the species 

 obtained in a single haul of a trawl in the Irish Sea. (Tie^j. Brit. 

 Assn., 1895, p. 713.) This haul was recorded in order to find the 

 number of species and genera represented on the ground, and un- 

 fortunately no information is given as to the relative abundance of 

 each species. It is therefore impossible to get a good idea of the 

 characteristic nature of the fauna on the ground. On the whole it 

 resembles that found on the grounds to the west of the Eddystone, both 

 the gravel and fine sand faunas being represented. It is of interest to 

 note that Chaeto2)terus and Halccmm hakcinum are both recorded and 

 that Fusus antiquus is present, whilst Buccinum undatum is absent. 



In the Proceedings of the Liverpool Biological Society (No. 40) Herdman 

 also records several grounds where ophiurids occur to the almost entire 

 exclusion of other species, a condition of things similar to that occurring 

 on Ground X., to the west of the Eddystone (c/. pp. 416 and 499). 



Geographical Distribution. Following Michaelsen (No. 79), three 

 of Forbes' geographical provinces have been recognised, under the names 

 Arctic, Boreal, and Lusitanian. The Boreal province contains the 

 greater part of Forbes' Celtic. The Arctic province (A.) Michaelsen 

 regards as bounded on the south by a line commencing at Cape Kace in 

 Newfoundland, running parallel to the south-east coast of Greenland, 

 cutting oiT the north corner of Iceland, and then striking the Scan- 

 dinavian coast at the Lofoten Islands. The Boreal province (B.) lies 

 south of this line, and comprises the temperate portion of the east coast 

 of North America, the greater part of Iceland, the greater part of the 

 Scandinavian Coast, the North Sea and the Baltic, and the British Seas 

 with the exception of the south coast. The Lusitanian province (L.) 

 extends from the English Channel to the Canaries and Azores, and 

 includes the Mediterranean. 



In Table VI., p. 529, the distribution of each species in the three 

 provinces has been indicated by the letters A. B. and L. Our know- 

 ledge of the true centres of distribution of the species is still too 

 imperfect in the majority of cases to make it possible to say whether a 

 species which is found in two provinces is equally at home in both, or 

 whether its centre of distribution occurs in one of the provinces and the 

 species must be regarded merely as an immigrant into the other. 



Species extending from the Arctic Seas to the Mediterranean, Azores, 

 and Canary Islands are indicated by the letters A.L. ; those which are 

 found in the Arctic and extend throughout the Boreal region by A.B.; 



