82 



THE AUSTRALIAN MUSEUM MAGAZINE. 



Dugongs on a northern beach. 



The eliief value of the dugong is the 

 oil yielded by the liver. The quantity 

 varies very considerably, sometimes as 

 much as eight to ten gallons being- 

 taken from a single individual captured 

 during the winter months, but on an 

 average only four or five gallons are 

 o])tained. The oil is peculiarly clear, 

 lim])id, and free from disagreealile smi'll, 

 and is largely in demand for medicinal 

 purposes. 



DEXIZEXS OF THE MAXGR0VE8. 



Although the coral reefs, Avitli tlieir 

 kaleidoscopic array of life, fascinate 

 the ol)server, nevertheless the mainland 

 can lay claim to some very curious 

 forms such as the goggle-eyed man- 

 grove fish, the calling or fiddler crab, 

 and the ant-house jDlants. Where the 

 shore is not exposed to strong surf it 

 is usually invaded by certain kinds of 

 trees forming a net-work so dense tliat 

 it is often very difficult to make a 

 landing. The mangrove is the most im- 

 portant tree of this kind. It grows 

 freely in the shallow sea water on low 

 and nmddy shores, and protects the land 

 from the waves. The roots grow in a 

 loop-like fashion, the up]ier portion be- 

 ing out of the ground at varying dis- 

 tances from a couple ol' feet down- 

 wards, and tims form a network around 

 the tree. The roots of these trees are 



often heavily encrusted with oysters 

 and barnacles. Muddy sediments ac- 

 cumulate in the (|uiet water among the 

 trees, and thus the land gains on the 

 sea. 



The jumping mangrove fish (Perio- 

 ptlndnms loelreuteri) are found in 

 great abundance on the mud flats and 

 among the network of I'oots of the man- 

 grove trees left l)are by the retreating 

 tide. These small fish skip about by 

 means of the muscular, scalv base of 



The loop-like roots of the Mangroves where 



muddy sediments accumulate, and thus the 



land gains on the sea. 



Photo — A. R. McCiilloch. 



