140 PROF. W. J. DAKIN : EXPEDITION TO THE 



At Geraldton, the nearest port to the Abrolhos and in the same latitude as 

 the islands, the sea temperature ranges from about l(3 - 7° 0. in winter to 

 23'5° C. in the summer. 



[For purposes of comparison the air temperatures taken in the shade at Geraldton during' 

 the three years 1913, 1914, and 1915 are appended. I am indebted to the Common- 

 wealth Meteorological Bureau for this information.] 



Shade Temperatures at Geraldton in °F. 





Year. 



Jan. 



Feb. 



Mar. 



Apt. 



May 



June 



July 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Mean max. 



1913. 



83-9 



85-6 



83-2 



78-7 



78-9 



72-6 



68-7 



67-9 



72-9 



72-5 



76-4 



77-5 



Highest . . 





99-3 



106-5 



107-2 



94-6 



900 



82-0 



80-0 



74-2 



95-0 



86-1 



1040 



103-3 



Mean min. 





64-5 



66-8 



65-1 



61-0 



55-5 



55-6 



48-6 



51-7 



51-0 



55-5 



58-6 



62-9 



Lowest . . 





56-0 



54-3 



54-5 



51-4 



47 



47-0 



37-3 



43-0 



39-0 



46-3 



47-0 



52-8 



Mean max. 



1914. 



85-0 



83-3 



82-6 



75-1 



72-6 



71-0 



67-6 



73-2 



76-7 



77-0 



77-1 



79-6 



Highest . . 





109-8 108-3 105-8 



84-0 



89-8 



83-8 



74-2 



84-0 



95-0 



97-8 



95-0 101-8 



Mean min. 





65-6 



64-3 



62-6 



56-3 



52-2 



51-5 



50 



52-0 



53-8 



60-6 



62-5 



650 



Lowest . . 





57-5 



54-5 



47-0 



44-0 



40-8 



43-0 



39-0 



430 



42-0 



49-0 



53-0 



55-4 



Mean max. 



1915. 



86-3 



84-4 



84-0 



82-7 



76-0 



71-4 



68-5 



69-4 



67-8 



72 9 



81-9 



86-6 



Highest . . 





100-0 



106-8 



99-0 



97-2 



84-8 



81-8 



74-6 



78-3 



69-8 



960 



1046 



113-0 



Mean min. 





69-3 



69-0 



64-1 



64-2 



58-5 



58-3 



54-5 



544 



53-5 



56-3 



61-0 



66 



Lowest . . 





59-0 



60-8 



54-2 



53-0 



50-8 



530 



41-6 



42 



46-2 



460 



51-0 



54-6 



If sea temperatures are taken a few miles away from the coast in the 

 region between Geraldton and Shark's Baj% it will be found that these off- 

 shore waters are somewhat warmer than those close to shore in the same 

 latitude. 



Now this is an important point, for statements have been made to the 

 effect that the marine fauna of the Abrolhos Islands contains so much of a 

 tropical element that one must travel up to the Tropic of Capricorn before 

 reaching a similar fauna on the coast. Whether this be correct or not*, the 

 fact remains that the Abrolhos are coral islets, and no coral reefs are met 

 with on the coast for many miles north of this latitude. The statements 

 about the tropical cbaracter of the Abrolhos fauna were first put forward 

 by Saville Kent, after his very short stay at the islands in 1894. He sug- 

 gested also as an explanation that an ocean current existed which set in from 

 the equatorial waters of the Indian Ocean and brought down floating larvse 

 without impinging on the adjacent coast. In support of this, Kent stated 

 that temperatures as low as 56° F. (13'3° 0.) were recorded at Geraldton 

 when at the same time the temperatures at the Abrolhos were 14° F. higher 

 (21" 1° C. ). This is a very considerable difference — 14° F. between two 

 places 40 miles apart with oceanic conditions prevailing — and it is a great 

 pity that Kent did not give more details concerning his figures. 



* According to Mr. Alexander, who has just completed an account of the Fishes from the 

 Abrolhos, the greater number of species are distinctly Southern types (extratropical forms). 



