352 On the u British Area " in Marine Zoology. 



depth exceeding 20 fathoms. The changes in the fauna are 

 gradual, and are to a great extent more effected by the nature 

 or the temperature of the bottom than by the actual depth. 

 There are only two natural limits to representatives of flora 

 and fauna — 1st the littoral, where there is alternation of sub- 

 mergence and exposure ; 2nd, the termination of the Lami- 

 narian zone at 15-20 fathoms (commonly), where, with the 

 cessation of Algoid growth, there is also necessarily a cessa- 

 tion of phytophagous animals. Secondly, I know no reason why 

 the " 100 fathom line roughly corresponds with the beginning 

 of the declivity of the continental plateau," more than any 

 other depth does so. 



(2) The eastern limit proposed in this present paper divides 

 the " Dogger Bank ; " but practically it is impossible to say 

 from what exact part of the Dogger Bank Mollusca and other 

 animals come which naturalists obtain through the instru- 

 mentality of trawlers or long- line fishers ; but the so-called 

 " Dogger Bank " shells do not really come from the shallow 

 waters of the Bank, but from the il deeper water " which is 

 within its British border, and to the north of it. 



(3) The chief object of the present paper has been to prove 

 that the "abysmal floor of the ocean" commences at 1500 

 and not at 1000 fathoms, and that depths of 1000 fathoms are 

 not to be found on its floor. In the Report the only boundary 

 given for the north is the 1000 fathoms limit ; but in that 

 direction no such sounding can be found until lat. 63° N. is 

 reached. This is far into the Arctic Ocean, and brings us to 

 a point nearer to Faroe or Norway than to Shetland, and 

 although the slopes N. and W. of Shetland, which are those 

 descending to the Arctic Ocean, must in some degree be 

 embraced, it appears to me right that they should not be 

 descended to such a depth as would be characterized by water 

 at or nearly at freezing-point. The limit, as indicated in this 

 paper, to the north does not descend to water deeper than 

 300-400 fathoms. 



(4) The Channel Islands lie outside the British area 

 proper, and belong geographically to France, the naturalists 

 of which country do right in including them in their fauna 

 and flora. As, however, they belong to us, and are a 

 favourite and excellent collecting-ground for southern forms, 

 it is convenient to students that their animals and plants 

 should find a place in works on British Natural History. 



I feel confident that when the enlarged British Marine 

 Area is fairly realized it will act as a great stimulus to many 

 naturalists, who restrict their studies to what is " British," to 

 take means for its fuller investigation. A vast field remains 



