324 THE INDUCTIONS OF BIOLOGY. 



est times geologically recorded, down to our own time ; and we 

 have no visible evidence of superiority in the existing genera 

 of these orders. In his lecture &quot; On the Persistent Types of 

 Animal Life,&quot; Prof. Huxley enumerates many cases. On 

 the authority of Dr. Hooker, he stated &quot; that there are Carbon 

 iferous plants which appear to be generically identical with 

 some now living ; that the cone of the Oolitic Araucaria is 

 hardily distinguishable from that of an existing species ; that a 

 true Pinus appears in the Purbecks and a Juglans in the 

 chalk.&quot; Among animals he named palseozoic and mesozoic 

 corals which are very like certain extant corals ; genera of Silu 

 rian molluscs that answer to existing genera; insects and arach 

 nids in the coal formations, that are not more than generically 

 different from some of our own insects and arachnids. He 

 instanced &quot;the Devonian and Carboniferous Pleur acanthus ^ 

 which differs no more from existing sharks than these do 

 from one another; &quot; early mesozoic reptiles &quot;identical in the 

 essential characters of their organization with those now liv 

 ing ; &quot; and Triassic mammals which did not differ a nearly so 

 much from some of those which now live, as these differ from 

 one another.&quot; Continuing the argument in his &quot; Anniversary 

 Address to the Geological Society &quot; in 1862, Prof. Huxley 

 gave many cases in which the changes that have taken place, 

 are not changes towards a more specialized or higher organ 

 ization asking &quot; in what sense are the Liassic Chelonia infe 

 rior to those which now exist ? How are the Cretaceous 

 Ichthyosauria, Plesiosauria, or Pterosauria less embryonic 

 or more differentiated species than those of the Lias ? &quot; 

 While, however, contending that in most instances &quot;positive 

 evidence fails to demonstrate any sort of progressive modifi 

 cation towards a less embryonic or less generalized type in a 

 great many groups of animals of long-continued geological 

 existence ; &quot; Prof. Huxley added, that there are other groups 

 &quot; co-existing with them, under the same conditions, in which 

 more or less distinct indications of such a process seem to be 

 traceable.&quot; And in illustration of this, he named that better 



