THE ANIMAL KINGDOM. 163 



form. Some are like bells, others like globes, some like 

 stars, others resembling globes with spikes projecting. 

 All of these seem to be carved with the utmost care out 

 of ivory, something like the far-famed carved Chinese 

 balls, yet all so infinitely small that an immense 

 number of them only form a few grains of sand so fine 

 as to be almost impalpable. No organs by which this 

 secretion of silex forming these wonderfully beautiful 

 shells exist; the minute animal consisting simply, as 

 already stated, of a speck of gelatinous matter, which 

 it is impossible to reduce to further simplicity. "We 

 scarcely condescend," observes Lamarck, a celebrated 

 French naturalist,* "to examine microscopic shells, from 

 their insignificant size ; but we cease to think them insig- 

 nificant when we reflect that it is by means of the smallest 

 objects that Nature everywhere produces her most re- 

 markable and astonishing phenomena. Whatever she 

 may lose in point of volume, in the production of living 

 bodies, is amply made up by the number of .individuals 

 which she multiplies, with admirable promptitude, to 

 infinity. The remains of such minute animals have 

 added much more to the mass of materials which com- 

 pose the exterior crust of the globe, than the bones of 

 elephants, hippopotami, and whales." 



The last section of the Protozoa is that comprehend- 

 ing the Poriferaf or Sponges. 



The living sponge consists of an assemblage of amoeba- 

 like particles of gelatinous matter, which, however, instead 

 of forming shells, deposit a network of a horny or 

 calcareous character, and sometimes (especially those 

 found on our coasts) crystals of flint. 



The horny skeleton from which the film of animal 

 matter has been removed, becomes the sponge we use ; 



* Born, 1744 ; died, 1829. f Ponis> a passage ; Jero, I be;ir. 



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