I shall now quit this subject and proceed with the few remarks 

 I have to make on the general theory of the evolution of life. 



There is one argument in favour of the Theory of Evolution 

 which I think is patent to every one, and that is, that highly 

 developed forms are almost invariably larger than the lowly 

 developed ; or at any rate, that all animals of a large size are 

 highly developed, or, in most cases, at the head of the group thev 

 belong to. & r j 



I will illustrate this argument. 



The vertebrates are larger in size collectively than the inverte- 

 brates. Amongst the latter, the MoUusca and Annulosa are larger 

 than the Coelenterata, and the Ccelenterata than the Protozoa. 



But these postulates must be taken with certain limitations. 

 All animals are affected in the struggle for existence by so many 

 surrounding conditions, and their size depends very much upon 

 whether their bodies are sustained in the air, as in birds and bats ; 

 m the water, as in whales and fishes ; or simply by then- legs on 

 the land, as in the case of the mammalia, reptiles, &c. 



It is quite clear the rule holds good when the two extremes of 

 the animal kingdom are compared, and no one could dispute that 

 the Protozoa, mostly microscopic, are not only collectively, but in 

 all cases mdividually smaller than the vertebrates. 



But let us see whether the rule holds good amongst the verte- 

 brates themselves. 



The highest vertebrates, the mammalia, are larger than the 

 birds; but these latter suffer in size by the fact that most of the 

 species have occasionally to sustain their bodies in the air. But 

 if we take into consideration the ostrich family, the members 

 of which do not fly and are probably descended from win-less 

 ancestors, we must admit that the largest bird, even including 

 the extinct genus Dinomis, falls very short in size of the lar-er 

 mammalia. '' 



The rule holds good when the Birds are compared with the 

 Eeptiles, keeping steadily in mind that Birds have to sustain 

 themselves m the air as a general habit. 



The largest Reptiles, the Crocodiles and the Aligators are 

 aquatic, and must therefore be considered as not affectin- the 

 general question. " 



The rest of the genus of Saurians are mostly of very small size 

 such as Lizards, Geckos, and Skinks. 

 The other large Reptiles, as the Turtles, are also aquatic; and 



