MARINK ALGAL COMMLNIIIKS of IHR JIAN KKRNANDKZ ISLANDS 69I 



the current is irregular and occasionallv runs SW or S. This also a<4rees with 

 Plaik's own experience. Returnin<4 tVoni Masatierra to X'alparaiso end of March 

 1891, he measured 19° s C. 15 miles \i of Masatierra, and 16° 25 C. 130 miles 

 from Valparaiso; the next day, 20 miles from port, 14°. He concluded that, 

 alon<i^ this latitude, the cold current is less than 130 miles wide. 



I did not know Plath's paper when I published my preliminary notes 

 (1936), but my observations' on temperatures and the absence of all the large 

 cold-water Phaeopliyceae together with the presence of a more or less thermo- 

 philous element among the algae coininced me that islands are not within the 

 limit of the l'eru\ian current. My assertion that Macrocystis, etc. did not even 

 occur in the drift was, however, wrong. I had overlooked the statements of 

 Chilton (vol. Ill, p. 88) and Xilsson-Cantell (vol. Ill, pp. 484, 489), who 

 report Amphipoda and Cirripeds on floating Macrocystis found off the shore of 

 Masatierra, as indicated on the labels. This may be taken as a proof that the 

 Peruvian Current reaches the islands; nevertheless, it holds good that the sur- 

 face temperature is several degrees higher than in X'alparaiso bay or anywhere 

 along the coast of Central or South Chile. The contradiction is only ap{)arent, 

 however, and due to the different meanings given to the concept » Peruvian 

 Current ». 



L. c. I used the name »Mentor Current* for the current W of the »Hum- 

 boldt Current-. Berghaus (Physikal. Atlas, 1839) distinguished this and gave 

 it a partly easterly direction. Later, this name has been interpreted differently 

 by different authors (see GUNTIIER, Discovery Reports vol. XIII, p. 113), and 

 has been dropped as ambiguous. It is not mentioned by ScilOTT in his Geo- 

 graphic des Indischen und Stillen Ozeans > (1935)- 



The surface water of the Peruvian Current is cool. Its source is the West 

 Wind Drift; it is a Subantarctic current, but not Antarctic, though to some 

 extent influenced by the South Polar Current. Our present knowledge of the 

 hydrological conditions is well brought out on Maps XXIX and XXX in SCHOTT's 

 handbook. The Subantarctic-Subtropical convergence between the Peruvian Cur- 

 rent and the South Equatorial Current lies W of the Juan Fernandez ridge, 

 approaching the islands in winter and probably causing the irregularities in the 

 current direction observed. 



The surface isotherms (°C.) at Juan Fernandez, Valparaiso and Callao, taken 

 from Schott's maps XX — XXIII and Gl'XTllER's map on p. 225, are shown below. 



Juan Fernandez Valparaiso Callao 



February 19 — 20 17 — 18 19 — 20 



May 17—18 14—15 16 — 17 



August 13 — 14 12 — 13 16 — 17 



November 15 13 — 14 15 — 16 



Mean 16 — 17 14 — 15 17 — 18 



' Unfortunately, very few were taken. Two at the shore of .Masafuera read 19.8 ,"2 1917) 

 and 20.3 ('-2', respectively. 



