THE DAWN-ANIMAL AS A TEACHER IN SCIENCE. 225 



successive organisms, it appears, like its Creator, 

 eternal. 



This leads to another and very serious question 

 How long did lineal descendants of Eozoon exist, and 

 do they still exist ? We may for the present consider 

 this question apart from ideas of derivation and ele- 

 vation into higher planes of existence. Eozoon as a 

 species and even as a genus may cease to exist with 

 the Eozoic age, and we have no evidence whatever 

 that Archaeocyathus, Stromatopora, or Receptaculites 

 are its modified descendants. As far as their struc- 

 tures inform us, they may as much claim to be original 

 creations as Eozoon itself. Still 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 descendants diminishing in size or altering in 

 general form, while the characters of the fine tubula- 

 tion and of the canal system would remain. We need 

 not wonder if any sessile Foraminifer of the Nummu- 

 line group should prove to be a descendant of Eozoon. 

 It would be less likely that a Sponge or a Foraminifer 

 of the Eotaline type should originate from it. If one 

 could only secure a succession of deep-sea limestones 



Q 



