42 



THE AQUARIUM. 



by evaporation the bulb rises to the surface. The other 

 ordinarily floats on the surface, but sinks immediately 

 that too much fresh water has been added. By the 

 assistance of these little instruments the mean density 

 can be easily maintained. And now for the inhabitants. 

 The beginner would do well to try his hand with the 

 lovely sea-anemones, of which so many species are to be 

 obtained upon our coasts. One of the commonest and 

 hardiest of these is the Beadlet {Actinia mesembryan- 

 theniitni) to be obtained almost anywhere on the coast. 

 As an instance of the hardihood of this species we may 

 mention the case of "Granny," a specimen gathered more 

 than fifty years ago by Sir John Dalyell from the rocks 

 of North Berwick. This venerable Beadlet is still living 

 in a prosperous and thriving condition. At the death 

 of Sir John, it was handed over to the care of Prof. 

 Fleming, and afterwards passed to the late Dr. M'Bain. 

 He, on the prospect of death, was most solicitous to find 

 a proper guardian for such a treasure. Some to whom 

 he spoke declined to undertake so responsible a duty, 

 till at last Mr. Sadler, the curator of the Royal Botanical 

 Gardens at Edinburgh, cordially responded to the 

 request, and when last heard of the old lady was doing 

 well. She is not failing in her powers, in spite of her 

 age, for we hear that between the 4th of March and the 

 4th of October, 1879, she gave birth to twenty-seven 

 little beadlets, though this is a very small matter 

 compared with a circumstance which occured in 1857. 

 On one night in that year she produced no less than 

 240 young ones ! 



Many other species may be included, and to them 

 may be added a number of Periwinkles, and a few other 

 Molluscs, also Prawns, serptdce, Starfish, &c. To these. 



