Fig. 370. LYNGBYA CUTLERI^. 



Colour. A brilliant light grass-green. 

 Sicbstance. Yerj soft and delicate. 



Character of Frond. Excessively slender, gently waved, jointed threads {filaments)', 

 unbranched; fixed at base, but forming fleecy layers; floating freely under 

 water. 



Joints. About as long as broad; filled with bright green colouring matter (endoclirome), 



which afterwards contracts into a round spot in the centre. 

 Measurement. From ^ to 1 inch long. 



Fructification. Minute seeds (zoospores) formed of the colouring matter in the joints, 

 collected into a round central mass (sporiclitmn), which in due time bursts out. 



Hahitat. In estuaries. Exmouth, Miss Cutler. But the plant should be looked for 

 further. 



I^ow Hormotrichum Cutlerice. 



Fig. 371. MICROCOLEUS ANGUIFORMIS. 



Colour. A dull, dark green. 

 Substance. Soft; gelatinous. 



Character of Frond. Dense layers of small, snake-like tubes, tapering at their ends, 

 widening upwards; open at the tops; forming patches on mud. Tubes filled 

 (when fully developed) with numbers of very minute, stifi", straight threads 

 {filaments) ; whose tips issue from the open tops, and may be observed (under 

 a microscope) to wave backwards and forwards (oscillate). 



Measurement. The patches about an inch long. 



Fructification. Minute seeds (zoospores) formed of the colour-cells in the filaments; 



which cells then separate, and in due time drop out. 

 Hahitat. Coast of Wales. West of Scotland. Pools of brackish water near the 



shore. 



Fig. 372. OSCILLATORIA LITTORALIS. 



Colour. The mass verdigris-green; dried filaments deep green. 



Substance. The mass slimy; filaments elastic; when dry, membranaceous; scarcely 

 adhering to paper. 



Character of Frond. A thin layer of slender, straight, or slightly-curved threads 

 {filaments) ; generally twisted into bundles. Filaments apt to break into 

 needle-like fragments; unbranched; tubular; containing very narrow cylindrical 

 colour-cells, which show through; their division-lines conspicuous, at intervals 

 of about one-third the width of the filament. 



Measurement. Indefinite. 



Fructification. Minute seeds {zoospores) formed of the colour-cells in the filaments; 



which cells at last separate from each other and drop out. 

 Hahitat. Appin. In pools along the muddy sea-shore, flooded by spring tides. 



The filaments of this genus may be observed (under the microscope) waving 

 to and fro {oscillating) as if possessed of animal life. For this purpose a morsel 

 should be placed in a glass with a few drops of water. The reason of this 

 curious fact is not known. 



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