NO. 1 TAYLOR: PACIFIC MARINE ALGAE 31 



and 14 in the southern islands. There is clearly little difference between 

 the central and the southern islands respecting endemics; about half the 

 list are found in both groups ; Carpornitra luxurians occurred in all three. 

 The relationships of these 18 to the nearest similar species seem scatter- 

 ing and vague, though most often to other Pacific relatives. Of the 10 

 species of wider range, here again the distribution was scattering, being 

 about equally pantropic, of the Gulf of California, or ranging more widely 

 northward and southward on the coast. The strongest evidence of sub- 

 tropical or more correctly south temperate elements in the Galapagos 

 flora lies in the presence of Eisenia, Desmarestia, Dendrymenia, and some 

 of the Delesseriaceae. 



It seems now generally recognized that the Galapagos Is. may have 

 originated in a common land mass, but that there is no strong evidence of 

 connection with South America (Stewart 1911). The southern islands 

 are bathed by water sometimes as much as 10° cooler than the northern; 

 while the former receive the Humboldt Current, the northern are at least 

 at times subject to a warmer current from the Gulf of Panama (Hooker 

 1851). While such might bring land plants of Caribbean origin, the 

 isthmus which would facilitate this equally prevents the transfer of 

 marine algae. The distinction emphasized by Hooker between the islands, 

 different species of given genera being commonly peculiar to different 

 islands, is certainly not true of the marine algae, conformably with the 

 continuity of the sea in which they live. The problem of downstream 

 dispersal of species peculiar to the archipelago is overshadowed by the 

 importance of water temperature, the distances involved being short for 

 the dispersal of marine algae. 



It is evident, even from a casual inspection of the list of Rhodophyceae, 

 that they constitute the greatest variety in the marine flora of this area, 

 double the number of Chlorophyceae and Phaeophyceae combined, either 

 of genera or of species. It is further readily determined that the Rhodo- 

 phyceae are mostly from the littoral, to the extent of about half again as 

 many as are secured solely from deeper water. It is a varied flora, with 

 over 90 genera and 240 species. Most of these species and particularly 

 most from shallow water are of relatively small stature. 



The Rhodophyceae collected on Baja California are chiefly forms with 

 a northward range, not going into the southern tropics ; less than half as 

 many are apparently local in distribution, a few range far to the south 

 along the mainland coast of Mexico, but very few beyond, and there were 

 almost no pantropic or Gulf of California species there. There is little 

 relation between the Rhodophyceae of Baja California and those of the 

 Is. Revilla Gigedo; most of the red algae of this group of islands tend 

 to range to the south, and rather farther than Mexico itself. 



