xvii THE EVIDENCES OF EVOLUTION 341 



-^-3f f_ ' 



^^iwaK** ->i_ TBI^^ 



;>* 



** / y y'-^^Px 



|i ,<^si, 





FIG. 112. VARIETIES OF DOMESTIC PIGEONS ARRANGED AROUND THE 

 ANCESTRAL ROCK-DOVE (Columba liuia). 



(.Based on Darwin's figures.) 



are independent of one another ? How necessary it is if 

 all are branches of one tree. 



