383 Mr. W. Thompsou on Marine Vivaria. 



XXXV. — On Marine Vivaiia. By William Thompson, Esq. 

 I To the Editors of the Annals of Natural History. 



Gentlemen, Weymouth, April 8, 1853. 



Believing as I do that the suggestions of Mr. Warington, the 

 experiments of Mr. Gosse, and the successful adaptation by 

 Mr. Mitchell at the Gardens of the Zoological Society, of the 

 principle of maintaining a balance between animal and vegetable 

 life in confined sea-water, will cause Marine Vivaria to be gene- 

 rally introduced throughout the country ; it has appeared to me 

 that my contribution of notes thereon might possibly prove use- 

 ful. Since the spring of 18501 have unintentionally paid atten- 

 tion to the subject, as will appear. It has during the whole of 

 that time been a custom of mine in my almost daily rambles 

 along the sea-shore and very numerous dredging excursions to 

 bring home any marine animals I may have met with, and place 

 them in vessels filled with salt water in order to study their 

 habits. I began by changing the salt water of the littoral spe- 

 cies twice a day, leaving them without water for an hour or so each 

 time ; thus intending to represent the tides : this I could do as 

 the sea is not fifty yards from my house, consequently sea-water 

 is easily procured. It however struck me that the constant 

 changing of the water was attended with what might turn out 

 to be unnecessary trouble ; I then tried changing it only once a 

 week, many died in consequence, and those that survived (amongst 

 which were Carcinus meenas and Actinia mesembryanthemum) were 

 undoubtedly in a very sickly state. Some little time after, a 

 storm threw on the beach a quantity of weeds attached to pieces 

 of stone ; amongst them Delesseria sanguinea, D. ruscifolia, D. hy- 

 poglossum, also Rhodymenia laciniata, R. jubata, and jR. ciliata 

 attracted my attention by the beauty of their fronds. I took 

 them home and placed them in a vessel of salt-water which con- 

 tained Crustacea, Echinodermata, Testacea, Zoophytes and other 

 things the result of a day's dredging ; I watched them daily in 

 order to change the water as soon as I detected my prisoners 

 becoming sickly, and (with the exception of one or two that died 

 and which I removed) to my astonishment at the end of a month 

 the whole of the animals were healthy, and the water remained in 

 my opinion pure and limpid. This fact, through my ignorance of 

 the rudiments of " Chemistry of Creation," I did not set down 

 to the right cause. I however knew the efi'ect, and from that 

 time invariably placed a few marine plants in my vivarium, 

 knowing from experience that they prolonged the life of the ani- 

 mals, and at the same time did away with the necessity of a con- 

 stant change of water. It was my idea that the plants acted as 



