232 



this in the case of Primnoïdeae and Echinideae. The great 

 resemblance of the East-Atlantic with both the Indian 

 Océan and West-India and the great différence of forms 

 of West-India with the East-Paciflc brought Dr. Versluys 

 to the hypothesis that the communication of Atlantic and 

 Pacific over the New World is older than that over the Old 

 World. Of course our algological knowledge is not yet so 

 advanced, that we might make any conclusions in that 

 way. However the known facts seem to show indications 

 in that direction. For instance : West-India has 160 species 

 common to the Mediterranean, whilst this number is only 

 73 for the South-Atlantic with the Cape of Good Hope, 

 and for the Warm-Paciflc 75. We should not forget howe- 

 ver that the Mediterranean is a carefully worked out 

 région, whilst from the Warm-Paciflc as well as from the 

 West Coast of Africa and the Cape of Good Hope very 

 little is known. So we may by no means yet condemn 

 Murr ay's hypothesis of a communication round the Cape of 

 Good Hope in quartairn periods, where, with the great diff"e- 

 rences of climate just as well in the North as in the South 

 hémisphère, also the great currents had another direction. 



But the algological research of the West is not only 

 interesting for the gênerai geographical distribution of 

 algae. But the distribution of algae in this région itself 

 gives rise to spécial problems. So it seems that on Gua- 

 deloupe the marine flora consits principally of Florideae, 

 whilst Murray déclares to hâve collected mostly Chloro- 

 phyceae on Grenada, and even Spirogyra tropica, a fresh- 

 water form found in the Amazonewaters. Also in this col- 

 lection of Dr. J. Boeke most spécimens from St. Martin 

 and St. Eustatius were Chlorophyceae. What may be the 

 cause in this région with so complicated streamdirections 

 and so changeable saltconditions, cannot be said so easily, 

 but certainly it is worth while to be studied. 



The algae of the North Coast of South-America, easily 



