42 rnoCKEDlNGS OF THE 



the brain and central nervous system of Artliropods and Verte- 

 brates, It IS interesting to notice that C. Judson Jlenick, another 

 distinguished physiologist and psychologist, has recently compared 

 the two sets of organs (Address cf the Chairman of the Section 

 /oology ; American Association for the Advancement of Science, 

 190S), prnitnj in 'Science,' 1910, p. 7). Professor Herrick, 

 reviewing tiie subject without reference to any theory of ori^rin, 

 comes to the conclusions that the psychological procf'sses" of 

 Arthwpods and Vertebrates differ totallv ; that the difference of 

 Junction IS correlated with a fundamental difference of type under- 

 lying all superlicial resemblances, and which was " foreshadowed 

 lar back among the ancestral crawling things in which no truly 

 vertebrate character was manifest, foreshadowed merely bv a 

 structural type with different latent potencies." 



Professor Stanley Gabdixer, F.E.S., F.L.S., said :— Of the 

 many speakers only Dr. Gaskell has put forward a connected theory 

 which the rest have merely attempted to destroy. Their alter- 

 native plan IS by a line of evolution through JmpMoxus, but they 

 do not attempt to show us how this beast may have been produced. 

 Lnlortunately in the whole question of the Origin of Vertebrates 

 we have very few real facts upon which to base our views. Such 

 facts, so far as I can see, will be obtained from the study of 

 extinct forms, and it is a most curious fact that nowhere 'hns 

 Palaeontology yet shown a series of transitional tvpes between 

 distant groups. We have to content ourselves with conclusions 

 from analogies and proofs by j^^'ohahilities. We largely study 

 existing forms. The danger of this is \yell exemplified when 

 we consider the relations of Keptiles to Mammals. Both groups 

 as existing now must largely be traced to Theromorphs, of Avhich, 

 following Cope, minute and relatively punv forms probably br.incbed 

 off into each of the two ph via. Applying the ordinary terminology 

 ot Cope, it may be said that existing Reptiles have regressed and 

 that existing Mammals have progressed. AVe may now consider 

 this line as fairly weW established by analogies and p^rohahilities, 

 and it appears to me that it is a line almost of facts to which we 

 can appeal with considerable certainty for zoological canons. If 

 there is one point more than another which it shows it is surely 

 the paramount importance of considering the condition of the 

 central nervoi;s system a test of progression, as Dr. Gaskell 

 maintains. It demonstrates with certainty that his deductions 

 from the brains of living Vertebrates, as such a test, are absolutely 

 justified. In opposition to Professor Dendy I should claim that 

 the central nervous system is the best organ on which to trace 

 the changes of evolution. It governs every organ in the body, 

 and it must reflect in its own structure every change which those 

 organs undergo, every act of progression. 



Turning to Amphibia, we have no indications of their real 

 origin, and we have still less when we come to the Fishes. The 



