March, 190".] THE TICTORIAN NATURALIST. 225 



The only satisfactory explanation of the Tasmanian 

 alliance is a landbridge, and that a fairly recent one, 

 Avhere Bass Strait now lies. As regards the relationship- 

 of Australia and South America, they are closer than 

 those of Australia and any other continent. There is, 

 practically no relationship, for instance, with Asia. As 

 Australia must have obtained its land animals from some 

 where, we look then to South America as their source ; or 

 to put it more cautiously, the two continents must both 

 have obtained their animals from a common source, which 

 was long shut off from the rest of the world. 



Continents are not everlasting, " like mists they form 

 themselves and go." Parts now joined were once sepa- 

 rated, and parts like South America and Africa now 

 divided by sea were once joined. 



Some groups of animals are older than others, and the 

 older they are the more opportunities, they have had of 

 spreading. So we find tapirs on the Orinoco and in 

 Malaysia. 



The lecture concluded with the display of a series r)f- 

 maps, showing the probable distribution of land and water 

 at various epochs in the past. 



TIMBER AND TREES. 



By Ernest Lees, Teacher of Woodwork, Continuation 

 School, Melbourne. 



On Wednesday morning, 2nd January, 1907, Mr. Ernes,t 

 Lees, of the INIeibourne Continuation School, led the party 

 to study the trees of the district. 



The first halt was made under an old gum-tree, which 

 was surrounded by tea-tree scrub. Mr. Lees pointed out 

 that botanists placed the gum-tree {Eucalyftus) in the 

 same natural order {MyrtacecE) as the tea-tree {Leptos- 

 fermum), though to a casual observer they were not much 

 alike. The eucalyptus leaf was studied, and its falcate 

 shape, leathery structure, and oil glands noted. The 

 shadeless character of eucalypts was seen to be due to the 

 habit the leaves, have of turning edgeways to the sun. 

 How the stimulus is received and transmitted is not 

 thoroughlv known, but is comprehended under the term' 

 " negative heliotropism. " Sections made of the fr*ult 

 disclosed manv small seeds lying in the ovaries. 



