DIPS IXTO MY AQUARIUM. 259 



bell of the perfect creature, and a larger mass or tufted stalk 

 protruding from one side. " From this condition two widely 

 different results may proceed." In the one case a nucleus 

 develops into a perfect Vorticella, which at length breaks out of 

 the Acineta^ while in the other case the nucleus " breaks itself up 

 into a great number of tiny clear bodies, resembling Monads, 

 which soon acquire independent motion, and glide rapidly about 

 the cell formed by the inclosed Vorticella-body, as in a little sea." 

 " By-and-by, this body, together with the Acmeta wall, suddenly 

 bursts, and the whole group of Monad-like embryos are shot out, 

 to the number of thirty and upwards. The Acmeta now collapses 

 and disappears, having done its office, while the embryos shoot 

 hither and thither in newly acquired freedom . It is assumed, 

 on pretty good grounds, that these embryos soon become fixed? 

 develop stalks, which are at first not contractile, and gradually 

 grow into perfect Vorticellre, small at the beginning, but capable 

 of self-division, and of passing into the Acineta stage, and 

 gradually attaining the full size of the race." — (Gosse's Evetwigs 

 at the Microscope^ p. 491.) This speculation of Mr. Gosse's, 

 however, is not adopted, and Acineta is generally placed in the 

 order of Suctorial Infusoria^ which follows the Ciliated I?ifusoria. 

 Amongst the Ciliata, and therefore closely allied with Vorticella, 

 are the well-known Paramcecium, Epistylis, Vagi?iicola, and 

 Stentor, all of which are common enough. 



Artificial Sea-Water. — 



Common Salt ... ... 1*325 parts. 



Magnesium Sulphate 

 Magnesium Chloride 

 Potassium Sulphate 

 Water 



100 



55 



150 

 60 



About 50*000 



Dissolve each of the ingredients separately and mix the solutions. 

 Let stand for some hours, and finally add the balance of the 

 water. Test the specific gravity of the mixture, and if over i"o2 7 

 add enough fresh water to bring to this point. 



