Life's Dawn on Earth / Being the history of the oldest known fossil remains, and their relations to geological time and to the development of the animal kingdom

by Sir John William Dawson

Fig. 38. Archæocyathus Minganensis—a Primordial Protozoon. (After Billings.)

(a.) Pores of the inner wall.

Fig. 39. Archæocyathus profundus—showing the base of attachment and radiating chambers. (After Billings.)