ANNIVERSARY ADDRESS TO THE GEOLOGICAL SOCIETY 525 
modern Foraminifera is of more than generic value; nor are the 
oldest Foraminifera either simpler, more embryonic, or less differen- 
tiated than the existing forms. 
The Cavlenterata—The Tabulate Corals have existed from the 
Silurian epoch to the present day, but I am not aware that the 
ancient Hedvo/i/es possesses a single mark of a more embryonic or less 
differentiated character, or less high organization, than the existing 
Heliopora. As for the Aporose Corals, in what respect is the Silurian 
Paleocyclus less highly organized or more embryonic than the modern 
Fungia, or the Liassic Aporosa than the existing members of the 
same families ? 
The Afollusca—In what sense is the living IValdheiimia less 
embryonic, or more specialized, than the palzozoic Spzrifer; or the 
existing Rhynchonelle, Craniea, Discine, Lingule, than the Silurian 
species of the same genera? In what sense can Loligo or Spirula 
be said to be more specialized or less embryonic than Belemnites ; 
the modern species of Lamellibranch and Gasteropod genera than 
the Silurian species of the same genera ? 
The Aznulosa—The Carboniferous Insecta and Arachnida are 
neither less specialized nor more embryonic than those that now live, 
nor are the Liassic Cirripedia and Macrura; while several of the 
Brachyura which appear in the Chalk belong to existing genera, and 
none exhibit either an intermediate or an embryonic character. 
The Vertebrata—Among fishes | have referred to the Ccelacanthin 
(comprising the genera Cwlacanthus, Holophagus, Undia, and Alacro- 
poma) as affording an example of a persistent type; and it is most 
remarkable to note the smallness of the differences between any of 
these fishes (affecting at most the proportions of the body and fins, 
and the character and sculpture of the scales), notwithstanding 
their enormous range in time. In all the essentials of its very 
peculiar structure, the MJacropoma of the Chalk is identical with the 
Celacanthus of the Coal. Look at the genus Lefzdotus, again, per- 
sisting without a modification of importance from the Lias to the 
Eocene formation, inclusive. 
Or among the Teleostei—in what respect is the Beryx of the 
Chalk more embryonic or less differentiated than the Beryx /eneatus 
of King George’s Sound ? 
Or to turn to the higher Vertebrata--in what sense are the Liassic 
Chelonia inferior to those which now exist? How are the Cretaceous 
Ichthyosauria, Plesiosauria, or Pterosauria less embryonic or more 
differentiated species than those of the Lias ? 
Or lastly, in what circumstance is the Phascolotherium more 
