PROTOZOA. AMCEBA. 



373 



This shapeless mass is well known to microscopic observers 

 under the name of the Proteus (Amoeba dijftuens, fig. 206), 

 which, from the continual changes of shape it presents, is 



Fig. 206. Amoeba difflvens, or Proteus, in different forms. 



honoured with the name of a fabled god, who could be 

 either animal, vegetable, or mineral in his nature. This 

 curious animal presents us with the essential characters of 

 the large class Rhizopoda in their simplest form. It ap- 

 pears to be of an exceedingly voracious disposition, seizing 

 upon any minute aquatic animals or plants that may come 

 in its way, and appropriating them to the nutrition of its 

 own gelatinous body. The mode in which this tender 

 and apparently helpless creature effects this object is very 

 remarkable. The gelatinous matter of which it is com- 

 posed is capable, as we have seen, of extension in every 

 direction ; accordingly, when the Amoeba meets with any- 

 thing that it regards as suitable for its support, the sub- 

 stance of the creature, as it were, grows round the object 

 until it is completely enclosed within its body. The sub- 

 stances swallowed (if such a term be admissible) by this 

 hungry mass of jelly are often so large, that the creature 

 itself only seems to form a sort of gelatinous coat enclosing 

 its prey. 



Professor Ecker believes in an exact similarity of con- 

 tractile substance between that of the lower animal forms, 

 such as the Rhizopoda, and that observed in the Hydra. 

 He says : " The properties of this substance, in its simplest 

 form, are seen in the Amoeba, the body of which, as is 

 known, consists of a perfectly transparent albumen-like 

 homogeneous substance, in which nothing but a few 

 granules are imbedded, and which presents no trace of 



