152 



THE DAWN OF LIFE. 



inverted cone of carbonate of lime from an inch or 

 two to a foot in lengtli_, and witli its point buried in 

 the mud at the bottom of the sea^ while its open cup 



Fig. 38. Archcsocyathus Minganensis — a Primordial Protozoon. 



{After Billings.) 



(a.) Pores of the inner wall. 



extends upward into the water. The lower part 

 buried in the soil is composed of an irregular acervu- 

 line network of thick calcareous plates^ enclosing 



