1872.] 



Modes of Origin of Infusoria fyc. 



243 



Nearly all of them were very small ; but a few areas of medium size 

 were intermixed*. The smallest were not more than 4 6 1 uu of an inch 

 in diameter, and these separated themselves from the pellicle as single 

 corpuscles ; slightly larger areas broke up into two or three corpuscles ; 

 and others, larger still, into 4-10 corpuscles. In most of these small 

 areas, the corpuscles were formed with scarcely any appreciable alteration 

 in the refractive index of the matter of which they were composed : this 

 simply became individualized, so that the corpuscles separated from the 

 surrounding pellicle and from their fellows, still presenting all the ap- 

 pearance of being portions of the pellicle, and exhibiting from 4-10 

 altered Bacteria in their interior. In some cases the products of seg- 

 mentation soon developed into actual flagellated Monads in a manner pre- 

 sently to be described ; whilst in others they seemed to remain for a 



Fig. 1. — Simplest Mode of Development of Monads and Fungi from the 

 Pellicle, (x 1670.) 



a, a. First stage of differentiation of separate and aggregated corpuscles. 



b, b. Such corpuscles in more refractive condition, developing into Monads. 



c, c. Fully developed Monads. 



d. Larger area in first stage of differentiation. 



e. Eefractive corpuscles which will develop either into Monads or Fungi. 



/, /. More refractive corpuscles which give birth to mycelial filaments as in g, and 

 ultimately expand into a form of Penicillium (h), 



longer period in the condition of simple motionless corpuscles. Other 

 solitary corpuscles or small areas began to form in the pellicle in pre- 

 cisely the same manner, though they speedily assumed a highly refractive 

 and homogeneous appearance. Why some should undergo such a change 



* In these medium-sized areas segmentation was accompanied by the production of 

 homogeneous and highly refractive protoplasm. 



