268 RELICS OF PRIMEVAL LIFE 



descendants of Eozoon may have continued to exist, 

 though we have not yet met with them. I should 

 not be surprised to hear of a veritable specimen 

 being some day dredged alive in the Atlantic or the 

 Pacific. It is also to be observed that in animals so 

 simple as Eozoon many varieties may appear, widely 

 different from the original. In these the general 

 form and habit of life are the most likely things to 

 change, the minute structures much less so. We 

 need not, therefore, be surprised to find its de- 

 scendants diminishing in size or altering in general 

 form, while the characters of the fine tubulation and 

 of the canal system would remain. We need not 

 wonder if any sessile Foraminifer of the Nummuline 

 group should prove to be a descendant of Eozoon. 

 It would be less likely that a Sponge or a Fora- 

 minifer of the Rotaline type should originate from it. 

 If one could only secure a succession of deep-sea 

 limestones with Foraminifers, extending all the way 

 from the Laurentian to the present time, I can 

 imagine nothing more interesting than to compare 

 the whole series, with the view of ascertaining the 

 limits of descent with variation, and the points where 

 new forms are introduced. We have not yet such a 

 series, but it may be obtained ; and as Foraminifera 



