illustrating the Distribution of Marine Animals. 201 



lands and Fuegia. At the Falklands, Captain Ross, in 1842, 

 found the mean temperature of the sea for July, 38*73°, and 

 for August, 38-10° ; while in the middle of the Atlantic, on 

 March 24, latitude 52° 31' south, and longitude 8° 8' east, 

 the temperature was down to 34*3° F., and in 50° 18' south, 

 7° 15' east, it was 37° F. ; March 20, in 54° 7' south, on the 

 meridian of Greenwich, it was 33*4° F. The month of 

 March would not give the coldest temperature. 



The temperature of the sea along the south coast of 

 Fuegia sinks almost to 35°, if not quite, and the line of 35° 

 therefore runs very near Cape Horn, if not actually touching 

 upon Fuegia, 



North Pacific Ocean. — Isocryme of 80° F. — The waters 

 of the Atlantic in the warmest regions sink below 80° F. in 

 the colder season, and there is therefore no proper Super- 

 torrid Region in that ocean. In the Gulf of Mexico, where 

 the heat rises at times to 85° F., it sinks in other seasons to 

 74° and in some parts, even to 72° F. ; and along the Ther- 

 mal equator across the ocean, the temperature is in some 

 portions of the year 78°, and in many places 74°. 



But in the Pacific, where the temperature of the waters 

 rises in some places to 88° F., there is a small region in 

 which through all seasons the heat is never below 80°. It 

 is a narrow area, extending from 165° east to 148° west, and 

 from 7g° north to 11° south. In going from the Feejees in 

 August, and crossing between the meridians of 170° west 

 and 180°, the temperature of the waters, according to 

 Captain Wilkes, increased from 79° to 84° F,, the last tem- 

 perature being met with in latitude 5° south, longitude 175° 

 west, and from this, going northward, there was a slow de- 

 crease of temperature. The ship Relief, of the Expedition, in 

 October, found nearly the same temperature (83| °) in the same 

 latitude and longitude 177° west.* But the Peacock, in 

 January and February (summer months), found the sea- 

 temperature 85° to 88° F., near Fakaafo, in latitude 10° south, 

 and longitude 171° west. In latitude 5° south and the same 

 longitude, on the 16th of January, the temperature was 84° ; 



* See, for these facts, Captain Wilkes' Report on the Meteorology of the Ex- 

 pedition. 



