FUNCTION. 185 



prey on flesh ; that some were formed to roam at large for 

 their food, others to find it by parasitic attachment ; while 

 many, like the Crustacea of the lower old red, the sauroid 

 fishes of the coal period, and the reptiles of the lias, became 

 the scavengers of their respective times, and lived on the 

 decaying garbage of the river -bank and the muddy sea- 

 shore. The functional performance of each great class, as 

 well as of the life of each great geological epoch, has ever 

 been, Avithin its own limits, a complete and independent 

 system. A world of shell-fish littoral and deep-sea, se- 

 dentary and vagrant, phytophagous and carnivorous ex- 

 isted in the earliest waters. The gigantic sauroid fishes of 

 the palaeozoic were the functional representatives of the 

 secondary reptiles ; the secondary reptiles, in their marine 

 ichthyosaurs and plesiosaurs, their estuarine teleosaurs 

 and steneosaurs, their terrestrial hylaeosaurs and megalo- 

 saurs, and their aerial pterosaurs, were respectively the 

 whales and dolphins, the crocodiles and gavials, the ele- 

 phants and tigers, the bats and the birds, of their period. 

 At every stage of time, and under every type of life, analo- 

 gous functions have been unerringly discharged. Herbi- 

 vorous, insectivorous, carnivorous, and omnivorous, are at- 

 tributes alike of the fish, the reptile, the bird, and the 

 mammal ; walkers, swimmers, and fliers, with powers more 

 or less restricted, have ever occurred within the same great 

 classes. 



In the interdependencies of existence demand has ever 

 pressed on supply, decay trodden closely in the wake of 

 reproduction, and suffering been commensurate with enjoy- 

 ment. An ideal COSMOS of painless beatitude is a dream 

 and delusion. Pain and death are stamped on the earliest 

 records of life. From the beginning the flesh-eater has 

 preyed on the plant-eater, and the weak have ever suc- 

 cumbed to the strong, even as they do now. The struggle 



