29G GEOLOGICAL CONTEMPORANEITY IX 



it may afford a sufficient refutation of many of 

 them. 



The PROTOZOA. The Protozoa are represented 

 throughout the whole range of geological series, 

 from the Lower Silurian formation to the present 

 day. The most ancient forms recently made 

 known by Ehrenberg are exceedingly like those 

 which now exist : no one has ever pretended that 

 the difference between any ancient and any modern 

 Foraminifera is of more than generic value, nor 

 are the oldest Foraminifera either simpler, more 

 embryonic, or less differentiated, than the existing 

 forms. 



The CCELENTERATA. The Tabulate Corals have 

 existed from the Silurian epoch to the present 

 day, but I am not aware that the ancient Hdiolites 

 possesses a single mark of a more embryonic or 

 less differentiated character, or less high organisa- 

 tion, than the existing Helicpora. As for the 

 Aporose Corals, in what respect is the Silurian 

 Palceocyclus less highly organised or more embry- 

 onic than the modern Fungia, or the Liassic 

 Aporosa than the existing members of the same 

 families ? 



The Mollusca. In what sense is the living 

 Waldheimia less embryonic, or more specialised, 

 than the palasozoic Spirifer ; or the existing 

 Rhynckonellce, Cranice, Discince, Linguloe, than the 

 Silurian species of the same genera ? In what 

 sense can Loligo or Spirula be said to be more 



