426 EVENINGS AT THE MICROSCOPE 



ated; the sinuosities are smoothed, or deepened into gulfs, 

 or protruded into promontories; firths form here, capes 

 there; not by starts, but evenly, and with sufficient rapid- 

 ity to be appreciable to the eye while under actual ob- 

 servation; though the alterations are more striking if you 

 take your eye off the object for a few seconds, and then 

 look again; and still more so, if you try to sketch the 

 outline. Individuals vary greatly in dimensions; this 

 specimen is about one hundred and twentieth of an inch 



FORMS OF AMCEBA 



(Successively draivn from one individual). 



in long diameter, but others I have seen not more than 

 one-tenth as large as this, and some twice as large. 



Disregarding now this peculiarity of change of form, 

 which has procured for it the name of the old versatile 

 sea-god that was so difficult to bind, we will concentrate 

 our attention on some other points not less interesting. 

 That great bladder undergoes changes besides those grad- 

 ual alterations of place which are dependent on the gen- 

 eral form. It slowly but manifestly increases in size up 

 to a certain extent, when it rather suddenly diminishes to 

 a point, and immediately begins to fill again, as slowly as 

 before. These alterations go on with some regularity, and 



