370 Mr. R. Warington's Notes on Animals in small Aquaria. 



one place to another of an analogous creature, the young of 

 the Actinia, takes place in sea water, from their attaching them- 

 selves by their tentacula to some moving denizen, the hold being- 

 released very soon after they are forced from their original 

 attachment. 



Sea Water. 



Memorandum 1. 



In my previous experiments in this branch of the subject, 

 commenced in January 1852*, and of which some results were 

 communicated to the British Association at their meeting last 

 year at Hull f, I stated that the result of my experiments to 

 ascertain the kind of sea-weed best fitted for maintaining the 

 balance with the animal life was, under ordinary circum- 

 stances, in favour of the Chlorosperms, and that the Rhodo- 

 sperms submitted to the like conditions did not answer the 

 purpose desired and at the same time retain their colour and 

 beauty, inasmuch as they very soon became coated with a growth 

 of short green and brown Conferva? [Conferva tortuosa?), which 

 entirely mantled the whole surface of the fronds and destroyed 

 their characteristic appearance. During these investigations, 

 however, it occurred to me that it might be possible to obviate 

 this drawback, and I have, I believe, succeeded, after a series of 

 experiments, in overcoming this inconvenience, and can now 

 retain them in all their natural loveliness and render them quite 

 efficient for all the purposes required, that is, as consumers of 

 carbonic acid and generators of oxygen. 



The ground on which I have reasoned as a basis for these 

 experiments has been the consideration, that nearly the whole of 

 these red or pink-coloured sea-weeds are found either in deep 

 water or under the shade of other Algae, and from the fact that 

 they were also often known to occur in shallow rock-pools ; it was 

 hence fair to assume that the pressure of the column of water 

 could not be an important element in the production of these 

 coloured growths, and therefore that it must depend upon a 

 modification of the light. Hence my idea was that the effects 

 of the depth of the water might be capable of being imitated 

 by tinting the light through the interposition of coloured 

 media, and thus all the results observed in the vegetation, and 

 much even of the healthy animal life of deep sea water could be, 

 under this arrangement, assimilated ; and this, I am happy to 

 state, has proved experimentally to be the case, so that, by very 



* Garden Companion, January 1852; and Annals and Mag. Nat. Hist. 

 for October 1852. 



f Annals and Mag. Nat. Hist. November 1853. 



