259 



range given by WiHey, one would scarcely consider as pro- 

 bable a migration via the western coast of Australia. The 

 one isolated statement by Menke is apparently the only record 

 on the western coast, and then, presumably, of a dead 

 specimen. At the same time, if there were evidence to show 

 that Nautilus did migrate down the western coast, all other 

 conditions are available to account for the specinaen in Foul 

 Bay, on Southern Yorke Peninsula. 



A migration, however, along the warm Notonectian 

 current, which sweeps past the home of the species, and 

 then down the eastern coast of Australia, seems more 

 probable. 



Waite (12), in the ''Thetis" Scientific Results, and 

 Hedley (13) both discuss the question and cite cases of the 

 migration of tropical life by this medium. This warm current is 

 not at all superficial, the depth being given by Dannevig (14) 

 as several hundred fathoms. By this medium the migrating 

 Nautilus could well arrive at a position east of Bass Strait 

 and Tasmania. How it could then travel westwards against 

 the easterly current from the Great Australian Bight must 

 be considered. Writing of the Notonectian current in 1910, 

 Hedley (15) says, "Neither its origin nor its conclusion has 

 been satisfactorily determined." * It is well known that upon 

 it-s being met by the easterly current from the Bight, in 

 Tasman Sea, it is, in part, deflected towards New Zealand. 

 As to whether a portion of its volume may continue as a 

 warm submerged current with a westerly drift is still to be 

 determined by accurate survey. (-) Dannevig (16) mentions the 

 possibility of such a ''deep sea circuit" in studying the migra- 

 tion of the mullet as one to be examined. 



Reference is here made to the Bibliography appended 

 for charts dealing with ocean currents affecting the Aus- 

 tralian coast. 



In discussing the distribution of asphaltum on the 

 southern Australian coast. Ward (17) publishes a chart showing 

 the distribution and trend of the principal currents. This 

 chart apparently covers the observations of all previous 

 charts, and is probably the most complete one issued to date. 

 It takes into account the well-known eddy in the Great 

 Australian Bight, which is not shown in the other charts. The 

 'Commonwealth Director of Navigation kindly referred the 

 writer to the "Admiralty Monthly Current Charts." 

 Attempts to see these have so far not been successful. From 

 ■all the other charts, however, accompanying the articles, and 



(1) Such A consideration may not appear physically sound. 

 It is mentioned here on account of its advocacy by Dannevig. 



