30 THE DAWN OF LIFE. 



to an enormous size, and by the aggregation of individuals 

 assuming the aspect of a coral reef. 



" The complicated systems of tubuli in the Laurentian fossil 

 indicate, however, a more complex structure than that of any 

 of the forms mentioned above. I have carefully compared 

 these with the similar structures in the 'supplementary 

 skeleton' (or the shell-substance that carries the vascular 

 system) of Calcarina and other forms, and can detect no 

 difference except in the somewhat coarser texture of the tubuli 

 in the Laurentian specimens. It accords well with the great 

 dimensions of these, that they should thus thicken their walls 

 with an extensive deposit of tubulated calcareous matter ; and 

 from the frequency of the bundles of tubuli, as well as from 

 the thickness of the partitions, I have no doubt that all the 

 successive walls, as they were formed, were thickened in this 

 manner, just as in so many of the higher genera of more 

 modern Foraminifera. 



" It is proper to add that no spicules, or other structures 

 indicating affinity to the Sponges, have been detected in any 

 of the specimens. 



" As it is convenient to have a name to designate these 

 forms, I would propose that of Eozoon, which will be specially 

 appropriate to what seems to be the characteristic fossil of a 

 group of rocks which must now be named Eozoic rather than 

 Azoic. For the species above described, the specific name of 

 Canadense has been proposed. It may be distinguished by 

 the following characters : 



" EOZOON CANADENSE ; gen. et spec. nov. 



" General form. Massive, in large sessile patches or ir- 

 regular cylinders, growing at the surface by the addition of 

 successive laminae. 



"Internal structure Chambers large, flattened, irregular, 

 with numerous rounded extensions, and separated by walls of 

 variable thickness, which are penetrated by septal orifices 

 irregularly disposed. Thicker parts of the walls with bundles 

 of fine branching tubuli. 



"These characters refer specially to the specimens from 

 Grenville and the Calumet. There are others from Perth, 



