ALG^. 145 



appeared under a weak lens, seemed as if covered by 

 chopped bits of hay, with their ends jagged. These 

 are minute cylindrical confervae, in bundles or rafts 

 of from twenty to sixty in each. Berkeley informs 

 me that they are the same species with that found 

 over large spaces in the Red Sea, and whence the 

 name of Red Sea is derived. Their numbers must 

 be infinite : the ship passed through several bands of 

 them, one of which was about ten yards wide, and, 

 judging from the mud-like colour of the water, at 

 least two and a half miles long. In almost every 

 long voyage some account is given of these conferva;. 

 They appear especially common in the sea near 

 Australia ; and off Cape Leeuwin I found an allied, 

 but smaller, and apparently different species. Captain 

 Cook, in his third voyage, remarks that the sailors 

 gave to this appearance the name of 'sea-sawdust.' 



Macdonald found the same, or a similar alga, off 

 the coasts of Australia, and in Moreton Bay, amongst 

 the Polynesian Islands, and on two separate occasions 

 off the Loyalty.Group, in nearly the same geographical 

 position. He says, ' When the filaments are first 

 removed from the water they may be observed ad- 

 hering side by side in little bundles or fasciculi ; and, 

 besides the colouring matter, the little cells, or at 

 least the intervals between the septa, contain glo- 

 bules of air, which sufficiently account for their buoy- 

 ancy ; and, moreover, in this respect, although their 

 abiding-place is the open ocean, their habit can 

 scarcely be regarded as very different from that of 

 those species which flourish in damp localties exposed 

 to the atmosphere. The filaments are all very short 



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