SURFACE TEMPERATURES. 25 



The existence of tliese large bodies of warm water in the western and 

 central area of the Pananiic region is well shown by the temperature sec- 

 tions (Pis. VIII, IX), Bull. M. C. Z. XXIII. No.l. The confusion existing 

 in the currents north of the Galapagos due to the How of the cold Humboldt 

 current between the southeastern islands of tlie Galapagos is easily traced in 

 Plates X-XII of the Report of the 1891 expedition. 



As we go southwest of Cocos the body of water becomes warmer, but 

 again becomes colder to the south of Malpelo and still colder to the east- 

 ward under the influence of the eastern branch of the Humboldt current. 

 Near Galera Point we find the same extremes of temperature in a small 

 bathymetrical range : 20° in less than 50 fathoms. 



SURFACE TEMPERATURES.! 



Plate 3'^'. 



On Plate 3" are found the curves of temperatures characteristic of the 

 Eastern Pacific from November to March. The heavy lines indicate tem- 

 peratures of 65\ 70', 75', and 80'. As the surface temperatures are known 

 only along the lines run by the " Albatross," they are of course not simul- 

 taneous observations. A glance at Plate 3" shows the two great warm 

 areas above 80". One south of the equator, east of the Marquesas and the 

 Paumotus ; this is somewhat pear-shaped, while the corresponding warm 

 area, nearly in the same position north of the equator, is elongated in shape 

 and extends east almost to 100" W. Long. A smaller warm area, bounded 

 by the 80 curve, runs parallel in a general way to the trend of the Central 

 American and Mexican coast. Within this area are smaller areas of greater 

 degree of temperature. The effect of the southeast trades in pushing west- 

 ward a large body of warm water close to the equator, and with a tempera- 

 ture between 75' and 79', is well shown on Plate 3'*. 



A huge body of water, with a temperature of between 75" and 80°, oc- 

 cupies the greater part of the Eastern Pacific. Next come the warui areas 

 over 80'. A mass of water, with a, surface tempei'ature between 70' and 75°, 

 extends from Lat. 20' S. and about Long. 94' W., to Long. 110' W., and 

 runs north to the latitude of the Galapagos in the west, when the 75' line 

 runs east toward the coast of Ecuador. The eastern face of this belt runs 

 north to the latitude of Aguja Point, when it runs in a northeasterly direc- 



1 For record of surface temperatures see List of Stations pp. 37-50. 



