444 THE MICROSCOPE. 



on each other, so as to make their rims or upper edges 

 meet. 



The other fossil Infusoria, found most abundantly in the 

 chalk and flint of England, are the Rotalia, or wheel-shaped, 

 and the Textularia or woven-work animalcules ; the latter 

 having the appearance of a cluster of eggs in a pyramidical 

 form, the largest being at the base, and lessening towards 

 the apex. 



We must here brins: to a close this short notice of 

 some of the marvellous creations in the invisible world , 

 every glimpse inspiring awe, from the immensity, variety, 

 beauty, and minuteness of its organised habitants. Immen- 

 sity, in its common impression on the mind, hardly conveys 

 the idea of the myriads upon myriads of Infusoria that 

 have lived and died to produce the tripoli, the opal, the 

 flints, the bog-iron, the ochres, and limestones of the world. 



Professor Owen beautifully explains the uses of this vast 

 amount of animalcule life : — " Consider their incredible 

 numbers, their universal distribution, their insatiable 

 voracity ; and that it is the particles of decaying vegetable 

 and animal bodies which they are appointed to devour 

 and assimilate. Surely we must, in some degree, be in- 

 debted to these ever-active, invisible scavengers, for the 

 salubrity of the atmosphere and the purity of water. Nor 

 is this all ; they perform a still more important office in 

 preventing the gradual diminution of the present amount 

 of organised matter upon the earth. For when this matter 

 is dissolved or suspended in water, in that state of com- 

 minution and decay which immediately precedes its final 

 decomposition into the elementary gases, and its con- 

 sequent return from the organic to the inorganic world, 

 these wakeful members of nature's invisible police are 

 everywhere ready to arrest the fugitive organised particles, 

 and turn them back into the ascending stream of animal 

 life. Having converted the dead and decomposing par- 

 ticles into their own living tissues, they themselves become 

 the food of larger Infusoria, and of numerous other small 

 animals, which in their turn are devoured by larger ani- 

 mals ; and thus a food, fit for the nourishment of the 

 highest organised beings, is brought back, by a short route, 

 from the extremity of the realms of organised matter. 



