244 H. J. WADDINGTON ON MARINE AQUARIA. 



very useful for bringing to the surface any particles of floating or 

 decomposed matters, and for giving a stimulus to animals that are 

 sluggish. For some Actinia, such as Anthea cereus, it is indis- 

 pensable, and it must certainly afford a nearer approach to the 

 conditions of their natural habitat, the sea, than to allow them to 

 remain constantly at rest. The syringe used should always be 

 pulled apart and left open after using, otherwise it will smell very 

 offensively. 



Well agitating the whole of an aquarium occasionally I have 

 found exceedingly beneficial ; I cannot better describe this than by 

 a " thorough stir up." It is a very heroic remedy, and I can quite 

 understand exception being taken to it, but the healthiest aquarium 

 I have, and the one which contains the most animal life in propor- 

 tion to its size, and in which the inhabitants breed most freely, is 

 the one which undergoes this process frequently. After well stirring- 

 it up I pass a muslin net through it for some minutes ; this retains 

 the greater portion of the floating matter. I then syringe it well 

 and in a few minutes the surface is covered with debris brought up 

 by the fine bubbles of air. These are removed by the net. The 

 water is then very thick, but improves rapidly, and in a week has 

 recovered its usual brilliancy. 



The restlessness of its inhabitants is the best indication that 

 something is wrong with an aquarium, and a few sharp strokes 

 with a syringe will probably reveal the cause. If this is removed 

 with a glass tube stopped with the finger, the whole well agitated 

 and syringed, it will probably right itself in a few hours, especially 

 if it is exposed to a little stronger light than usual to aid the evolu- 

 tion of oxygen. It is somewhat remarkable how an aquarium 

 which is very bad both to sight and smell will recover itself under 

 these conditions. 



With regard to the stocking of an aquarium, I can offer little in 

 the way of suggestion as I have gone on no settled principle. 

 Living in London one has to take things as they come, and some- 

 times they come just when you are least prepared for them. My 

 own experience is that you cannot make an aquarium a happy 

 family of all kinds of Actinia. Even those that require nearly the 

 same conditions do not appear to thrive equally well when together, 

 and it will frequently be found that removal to another aquarium 

 will be followed by a great improvement. This is particularly 

 noticeable with Anthea, which I have found a most difficult anemone 



