XL 



A COMPARISON OF THE MARINE FLORAS 



OF THE W 'ARM ATLANTIC, INDIAN 

 OCEAN, AND THE CAPE OF GOOD HOPE* 



IN delimiting the above regions I have been guided by what may fairly 

 be taken to be their natural boundaries. The warm Atlantic is the tropical 

 Atlantic, with a slight northward extension, to include Florida, the 

 Bahamas, and Bermuda in the track of the Gulf Stream, and also Madeira 

 and the Canary Islands, washed by that branch of the same stream which 

 trends off backward to the south, the north equatorial current. I have not 

 included the Azores, since they are not sufficiently under this influence 

 and their marine flora, so far as we know it, appears to be more akin to 

 that of the north temperate Atlantic. On its southern boundary on the 

 African coast the Cape region is permitted to come slightly within the 

 tropics, so far as Walfisch Bay, on account of this coast being swept by a 

 cold current from the south, bringing with it up to this point at all events 

 such temperate forms as Laminaria, recently recorded from that place. 

 The Indian Ocean similarly is the tropical Indian Ocean, but including 

 the whole of the Red Sea, and extending to the south slightly outside the 

 tropics down the coast of Africa, and including the whole of Madagascar. 

 I am justified in this by the course of the warm Mozambique current. I 

 do not include on the east Sumatra, which appears to belong to another 



* A paper on this subject was read by me at the British Association at Edinburgh, 

 1892, and a table appears in the Report. The Cape totals in that table were much smaller, 

 since the present table embodies the results obtained since then by Miss Barton, alluded 

 to in this paper. 



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