THE LOWER FOEMS OF LIFE. 



35 



without muscles, feeling if it has any power of doing so without 

 nerves, and not only this, but in many instances forming shelly 

 coverings of a symmetry and complexity not surpassed by those of 

 any testaceous animals :" (pref., p. vii.) 



Now, there are two divisions especially under which I shall 

 endeavour to illustrate the peculiar history of this singular creature. 

 First, those which are either naked or else invested with a covering 

 softer than that afforded by shells. Secondly, those which form, 

 and live in, the beautiful shells known as Foraminifera. 



The first series are well represented by the Proteus-like Amoeba 

 found in fresh water, to which I have alluded above. It is, in fact, 

 the type of the family, and, having observed it changing its form, let 

 us now look at it while feeding. If you fix your attention upon the 

 creature, you will notice that some other animalcule or an atom of 

 vegetable matter will now and then come in contact with the body, 

 and seem to -be unable to get away again. In all probability this is 

 owing to an urticating power possessed by the Amoeba. Be this as 

 it may, its fate, if a living thing, is sealed. By a peculiar action of 



Fig. 36. 



Fig. 37. 



Fig. 38. 



Fig. 36. Food passing into the Amoeba. a, the food 6, the nucleus c, vacuoles or air 



spaces d, granules e, ectosarc /, endosarc. 



Fig. 37. Food breaking up into smaller parts in the interior of Amoeba. 

 Fig. 38. Undigestible parts of food passing out through coats of Amoeba at a. 



the protruded parts called pseudopodia, the object is pressed against 

 and through the outer covering or ectosarc, as it is termed, and then 

 through the inner envelope or endosarc into the interior of the cell, 

 called an Amoeba. The structure of the creature is simply two 

 coverings inclosing a softer portion of sarcode, having contents very 

 similar to those described in the Infusoria. Having thus been forced 

 through the sarcodous envelopes, the substance breaks up into 

 granules, which are sent round the fluid in the interior of the bag, 

 during which process all that is nutritious is extracted, and that 

 which cannot be assimilated collects on the opposite side, and makes 

 its way through the two coverings out again. These several events 

 are illustrated in Figs. 36, 37, 38. 



D2 



