264 



THE POPULAR SCIENCE MONTHLY. 



In Fig. 3 we have an enlarged restoration, after Dawson, of a por- 

 tion of the EozoOn structure, which will enable us to better appre- 

 ciate the several parts of the organism. The dark, granulated layers 

 at the base and at intervals higher up constitute the chambers, and con- 

 tain the sarcode or gelatinous animal matter. Immediately above and 

 below each dark layer is the thin calcareous shell penetrated by the 

 minute orifices or tubuli. The white spaces represent the supple- 

 mentary skeletons traversed by the larger canals. At the summit the 

 sarcode is developed into several pseudopodia or cilia, by means of 

 which food is brought to be assimilated. 



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< Jfil I / X 



Clc W 1 J 





i - * - ii.iliiin iiiilirv- J" -Ti^;^ >/ ..v>v~' i 'SS J.iuu.i 111 ] |i 



Fig. 3. Eozoon restored. (After Dawson.) 



In Fig. 4 we have a portion of Eozoon magnified one hundred diam- 

 eters, drawn by Carpenter. The upper covering (a a) represents the 

 original cell-wall penetrated by the tubuli or pores in great abun- 

 dance. A bit of this is still more magnified in 2, by the side of the 

 first, seemingly consisting of an upper and lower part. The greater 

 part of the sketch consists of the supplemental or intermediate skele- 

 ton, traversed by two kinds of canals (b, c), of much larger size and 

 greater irregularity than the tubulation of the cell-wall. 



The arrangement and composition of the mineral matter of the 

 Eozoon is quite interesting, and the more remarkable since it has 



