structures consist of a series of compartments, in the interior of 

 which the semi-fluid substance of the animal is lodged. The walls 

 of each of these compartments are perforated with innumerable 

 holes, through which the slender glass-like filaments protrude in 

 all directions to a considerable distance, so that the shell in which 

 the main body of the creature is encased, has somewhat the ap- 

 pearance of a spider sitting in the centre of its web. (Fig. 5, &.) 



The semi-fluid filaments (psfudo-podia} also constitute the pre- 

 hensile organs of these simple beings. Any small objects sen 

 able for nutriment with which they come in contact are laid hold 

 of apparently by the viscidity of their surface, and except they 

 are animalcules of considerable size and power, they are unable 

 to escape. When a filament has so seized its prey, adjoining 

 fibres aggregate about it and coalesce, a current of the viscous 

 substance, so to speak, sets in towards the spot, and very soon 

 envelopes the object in a thin film. The prey being thus secured. 

 the glairy cords shorten themselves and draw it towards the chief 

 mass or body of the animal or else the object seized continues in 

 the same place, and the whole organic substance moves towards it, 

 the result being in either case that it is engulfed and dissolved. 



The size of the Rhizopods is exceedingly minute. Ehrenberg 

 describes Anurbtr the dimensions of which range from 1^00 th to 

 T^T th of an inch. The largest fresh-water forms only attain a 

 diameter of ^*nd part of an inch, whilst the largest marine species, 

 which are just visible to the naked eye, do not measure more than 

 from -s\;th to |th of an inch. 



vithstanding their minuteness, however, the reader will now 

 begin to perceive that these humble creatures, diffused in count- 

 less multitudes through every sea, and cased in shells of such ex- 

 quisite workmanship, are by no means unimportant agents in the 

 economy of Nature. Their numbers make up for the minuter.. 

 of their dimensions, and assiduously employed as they have been 

 from age to age, we are not surprised to find that they, like the 

 vegetable forms described in the last chapter, have been important 

 agents in the construction even of extensive geological strata. 



The extraordraaiT abundance of focammiferoos shells in the sand of some 

 ; has been long observed: F1ancas,in 1735, counted, with the aid of 



:: ::.; Air.-.; S-. 1 J : : - . 5-;.; -J-i: :.:_;;,;,; 

 ; and Schnhz 



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