CHAPTER VII. 

 CONCLUDING REMARKS. 



IN the preceding chapters we have obtained a glimpse 

 and only a glimpse of the Animal Kingdom as it now 

 appears on the surface of the globe. 



But the animals of the present, vast as are their num- 

 bers, are but a handful compared to those that have occu- 

 pied the surface of the earth in past geologic ages, and that 

 are now known only by their remains, which fill the rocks 

 in many countries to the depth of six or eight miles or 

 more. 



Nature has embalmed these races, and handed them 

 down to us so perfectly preserved, that we are able to get 

 at least a faint view of the phases of life during all the 

 past agos of the world. And it is a fact of the highest 

 significance, that the animals of the past, and those of the 

 present, are built according to the same great plan. Pro- 

 tozoans, Radiates, Mollusks, Articulates, and Vertebrates 

 are all the types under which animal life has been ex- 

 hibited upon the earth. 



When we consider the branches, the classes, the orders, 

 the families, the genera, the vast number of living, and 

 perhaps the much greater number of extinct species, and 

 then consider that each species is represented in many 

 cases by millions of individuals, and that probably no two 

 individuals, even of the same species, are exactly alike in 

 every particular, and yet that each one of all these count- 

 less millions bears within itself the stamp of a Protozoan, 



