EVOLUTION AS A FACT 483 



Feather -Stars have descended from fixed forms resembling the 

 related Sea- Lilies, some of which still live in the deep sea. 



THE ARGUMENT FROM THE GEOLOGICAL RECORD. Although 

 our knowledge of the successive faunas which have existed in 

 the course of the earth's history is lamentably incomplete, all 

 the facts with which we are acquainted harmonize with the 

 doctrine of evolution (see p. 456). There has been a general 

 progress from low to high, and many animal pedigrees have 

 been worked out in considerable detail. Taking Hoofed Mam- 

 mals and Flesh- Eaters, for instance, the geological record shows 

 that the existing subdivisions of these orders can be traced back, 

 respectively, to common ancestors (see p. 472). The most 

 ancient birds known possess characters which are strong evidence 

 of reptilian descent, and Reptiles, in their turn, are in all pro- 

 bability an offshoot from an amphibian stock. Similar evolu- 

 tionary conclusions can be drawn in all cases where sufficiently 

 abundant evidence is available. 



THE ARGUMENT FROM GEOGRAPHICAL DISTRIBUTION. The 

 way in which animals are at the present time distributed over 

 the face of the globe is susceptible of no satisfactory explanation 

 unless we have recourse to the theory of evolution. Admitting 

 this, and at the same time making full use of the evidence 

 afforded by the geological record, many things which would 

 Otherwise be entirely unintelligible find an easy solution, as has 

 already been sufficiently indicated (see p. 409). We are able 

 in this way to understand why Tapirs are at the present time 

 only to be found in south-east Asia and tropical America, 

 Pouched Mammals in the Australian region and America, and 

 similarly for many other apparent anomalies. 



