MARINK AI.C.AI, (.OMMIM TIKS OI' THK JL'AN KF.RNANDKZ ISLANDS 695 



rc^artlcd as slow. W'liy some species remained unaltered, wjiereas others clianj^ed, 

 is an unanswered ([uestion, unless we assume that the former arc later arrivals, 

 which iiave not had time to chan<^e. Advocates of the trul\- oceanic nature of 

 all neovolcanic islands allow little tune lor the e\()lution of stron<;l\' marked 

 endemic forms. Affinities are with Australian forms in three cases (8 c), but 

 the majorit}' (8 h) are Tr()])ical or Subtropical in general and it seems reasonable 

 to link them with the West Pacific flora (Australia — I\Iala>'a — I'^ast Asia, and 

 Oceania), a fiora naturall\- enough feebl}' represented in the domain of the 

 I'eruvian Coastal Current. It is just as easy to understand that, while numerous 

 Magellanic algae extend north along the coast • — the large Phaeophyceae, 

 Macrocystis pvrifcra, Lessoiia lugricaiis and Durvillea a}itarctica are the most 

 conspicuous, but many smaller forms, both green, brown and red, reach as far 

 as Concepcion (36° 45' S) or at least to Corral or Chiloe (40 — 42°) — this group 

 (7) is very small in the Juan Fernandez flora (4 circumpolar species, with the 

 exception of Gojiiiiocaypus also found in New Zealand). 



It might be argued that the Subtropical element in the insular flora is 

 stronger than we have reason to expect judging from temperature conditions 

 alone, and that, consequently, historical cau.ses have been active. The fossil 

 land floras of South Chile and Antarctica show that during the Tertiary the 

 climate was considerably warmer than now; Antarctica, now ice-covered and 

 utterly barren, was forested. The temperature of the sea must have been higher 

 than now, the marine flora and fauna including, beside eurythermic forms, a greater 

 })roportion of macrothermic species, while microthermic and cryophilous species 

 did not thrive. The Pleistocene glaciation created catastrophal conditions for 

 the land flora and fauna and must have had a profound influence also on the 

 marine world. The West Wind Drift received a larger amount of Polar water 

 along its inner front, the temperature of the Peru Current was lowered, and the 

 difterence between inshore and offshore water may have been even greater then 

 now. A Subtropical element was able to survive in the islands, but disappeared 

 from the mainland. Postglacial changes have not been able to remove this dif- 

 ference, and have not allowed the insular endemics to extend their range. 



We may well ask where the microthermic Subantarctic and Antarctic organisms 

 lived during the Tertiary, when the temperature was much higher than now. It is 

 impossible to believe that the numerous genera and species which are more or less 

 strictly confined to the belt Fuegia — F"alkland — South Georgia— Kerguelen — New 

 Zealand inhabited the Antarctic continent during the warmest period of the 

 Tertiary and still more impossible that the present Antarctic flora existed there, 

 a flora not only composed of cold-resistant Subantarctic species but also of truly 

 Antarctic ones, among the algae such conspicuous genera as Cystospliacra, 

 * Ascoseira and the giant Phyllogigas among the browns, and Leptosarca among 

 the reds, and nobody would suggest that these remarkable endemics evolved 

 during or after the Glacial Period. Where did they come from.' In the case 

 of land plants, we may find a refuge in the mountains for microthermic species 

 during a warmer period, but where did the marine organisms go to, if the 

 position of the poles was the same as it seems to have been since Pleistocene 



