AMONG SIMPLE SA.ECODE ORGANISMS. 



405 



Carter, is very remarkable. Its peculiarity consists in the fact 

 that the cyst is not immediately surrounded by the outer shell of 

 the rhizopod, but by a second shell which lies within this and is 



Fig. 7. 



SM- 



Euglypka alveolata. 

 Encystation with the formation of a double cyst-covering. 

 a, the colourless shell formed of hexagonal plates and closed at d by aggluti- 

 nated foreign bodies ; b, the outer brown egg-shaped cyst-shell ; o, the inner 

 spherical colourless cyst-shell ; /, the homogeneous colourless cord which ex- 

 tends through the space between the inner and outer cyst-shell ; n, the clear 

 inner portion of the contents of the cyst, apparently corresponding to a nucleus. 

 (After Hertwig and Lesser.) 



completely closed. This inner shell is oviform, with the narrow 

 end turned towards the pseudopodial orifice of the outer shell, 

 within whicb it lies free and movable. Its structure resembles 

 that of the outer shell ; but it is of a light brown colour, which is 

 intensified by the application of sulphuric acid and iodine, while 

 these reagents cause no change in the colour of the outer 

 shell. 



Within the inner shell lies the proper cyst. This is of a 



