302 CATALOGUE OF MARINE ALG^ OF WEST INDIAN REGION. 



I venture to think that the conclusion is obvious enough, from 

 the foregoing tables, that the West Indian Region is a natural one. 

 At the beginning of the work the inclusion of Bermuda in the region 

 seemed to rest on doubtful grounds, but on the whole, these doubts, 

 such as they were, have been removed during its progress. The 

 occurrence on that island of two sjpecies of Fucus, for example, viz., 

 F. ceranoides L. and F, distichus L., certainly makes one pause, but 

 a consideration of the whole of the list containing many examples 

 of peculiar West Indian forms outweighs this evidence of a northern 

 flora — and we may safely regard Bermuda as no longer "vexed," 

 but well established as the northern limit down the Gulf Stream of 

 this region. The other difficulty in delimiting the frontier of the 

 West Indian Region has been the wide question of how far it is 

 worth while separating it from the warm Atlantic region. It will 

 be seen that the latter exceeds by only one the total for the 

 Mediterranean of West Indian forms common to the regions in 

 question — but it must not be forgotten that the Mediterranean not 

 only ofters a long coast-line, but it has been far better explored for 

 Algae than the coast-lines of the warm Atlantic region. Compare 

 our knowledge of the Algae of the Adriatic or of the Bay of Naples 

 with our poor records from Brazil or the West African coast ! 

 The proportion of warm Atlantic forms occurring in the West 

 Indies (to put the case from the other point of view) — I mean the 

 proportion to the who?e known marine flora is far greater than the 

 proportion of Mediterranean forms so occurring. While therefore 

 maintaining the West Indian region for the present, I should offer 

 no serious opposition to its being engulphed in the warm Atlantic 

 region if it be considered desirable to deal with regions of larger 

 area. 



The total of species common to the Cape may cause some 

 surprise as to its smallness compared with Australia. This, I take 

 it, is to be accounted for by the two facts that Australia has been 

 ascertained to have a very large and varied marine flora, and that 

 this flora has been so thoroughly studied from the systematic point 

 of view. From Australia and the S. Pacific, I should explain that I 

 exclude North Australia. The material from Torres Straits, which 

 is about all we know of it, shows a greater relationship with Indian 

 Ocean and warm Pacific forms than with East, South, or West 

 Australian forms. The smaller totals from warm Pacific and 

 North Pacific are to be accounted for by the poverty of our 

 knowledge of these regions. 



The total from the Indian Ocean is at first sight most surprising 

 of all— in its being smaller than the Australian total. I have 

 included in this Indian Ocean region, the Red Sea, and islands, &c., 

 as far south as Mauritius, and as far east as Singapore. Granted 

 that the Australian marine flora is well known, it must also be 

 urged that the Indian Ocean as thus delimited has been by no 

 means neglected. Allowing that, of the two regions, Australia is 

 the better known, even then the result is surprising when we 

 consider the similarity of the physical conditions occurring in the 

 Indian Ocean and West Indian regions — and the enormous extent 



