486 



THE BEGINNINGS OF LIFE. 



of the encysted Amccbae known as Arcellinse '. In this 

 case, from the transforming substance of the dead 

 Rotifer portions of matter (a^ b) bud out, which, when 

 they have attained a certain size {c\ very frequently 

 divide into two parts, each of which becomes more and 

 more condensed externally, so as to produce an Arcella 

 with the characteristic cyst-like though perforated en- 

 velope (^, e). The forms of Arcellse produced in this 



Fig. 89. 



Arcellae and Peranema derived from Pangenesis of Rotifers. (Gros.) 



a, h. Bud-like outgrowths from the substance of a dying Rotifer, which 

 increase in size and at last form a mass (c), which divides into 

 two equal parts, each of which speedily takes on the form of an 

 Arcella {d). 



e. More completely developed form of Arcella. 



/. An Arcella whose animal substance has contracted within its 

 shell preparatory to further transformations. 



g. A Peranema produced from an individualized portion of the sub- 

 stance of a dying Rotifer. 



manner are of the most varied nature, though they all 

 protrude portions of their internal substance through 



^ They form a group of organisms which intervene between ordinary 

 Amoebae and those living in very complex chambered cells, which 

 are known by the name of Foraminifera. 



