THE WATER. 103 



masses of Corallina officinalis in the incrusting state. 

 Among the latter were three tufts of Griffithsia setacea, 

 one of Delesseria alata, two of Plocamium coccineum, 

 and one large and one small bush of Phyllophora 

 rubens. To these were added, about ten days after- 

 wards, a mass of Zostera marina. 



About 20 gallons of sea-water, dipped from the 

 quay steps while the tide was coming in, were poured 

 into the Tank, a plate being held under the stream, to 

 prevent the displacement of the contents by the falling 

 water. It was rather turbid at first, but soon cleared, 

 and in about two days became quite crystalline, 

 except a slight tinge of green, which always remained; 

 not enough to alter the hue of any object in the vessel, 

 but perceptible, by contrast with the clear air, when 

 the whole body of the fluid was looked through. 



No animals were put in till the third day ; but from 

 the weeds multitudes of minute creatures swarmed 

 forth, quite peopling the water. At night the applica- 

 tion of a candle revealed a vast number of tiny animals 

 clinging to the sides, and visible through the clear 

 glass ; Annelides of the genus Syllis ; Rissoce and 

 other minute shell-fish : hut principally Isopodous 

 and Entomostracous Crustacea, for the most part so 

 small, as to require a lens for their detection. The 

 careful examination of the water with the triple power 

 of a pocket lens made manifest also that an immense 

 number of Infusoria and some Rotifera were tenant- 

 ing the Tank. 



These, especially the Crustacea, could be drawn to 

 any part of the vessel by the moving of the candle ; 

 for when this was placed within an inch or two of the 



