EHIZOPODA. 5 



tition is performed by the Amoeba may not inaptly 

 be illustrated by forcing a stone into the interior 

 of a lump of clay or similar plastic material. The 

 power of selection possessed by the Amwba would 

 seem to be but slight, either as to the quantity or 

 quality of its food. Inorganic particles, such as 

 sand, are frequently ingested along with its more 

 proper aliment. Sometimes the body of the 

 Amoeba appears as a mere transparent film in- 

 vesting the substance swallowed, and it occasion- 

 ally happens that it becomes impaled on the sharp 

 point of some projecting object. The indigestible 

 remains of the food are finally pushed out through 

 some part of the gelatinous body. 



In the interior of the bodies of most Amoeboe a 

 central solid particle or ^ nucleus ' (v) may be 

 observed, and, at certain times, one or more clear 

 spaces or * vesicles ' may also be noticed. These 

 contractile spaces are not permanent, but are seen 

 to appear and disappear suddenly at more or less 

 regular intervals. The colourless fluid, which they 

 contain when dilated, would seem to be furnished 

 during the process of digestion. 



Physiologically, the Aiinoeba may be regarded as 

 the lowest of all animal forms, destitute of distinct 

 organs, any part of its gelatinous body being ca- 

 pable of performing the functions of locomotion, 

 digestion, &c., for the discharge of each of which 

 a special, and often highly complicated, apparatus 

 is set apart in the case of many of the higher 

 animals. But, notwithstanding this simplicity 

 of structure, several naturalists deem themselves 

 justified in regarding the more permanent varieties 

 of Amoeba as so many distinct species ; several of 

 which have been described and figured byAuerbach. 



B 3 



