PHYLOGENY. 



125 



developed among rasorial types in the sand-groiise, 

 and, among the adjacent forms, the pigeons. Then 





» I ^'8 32 — A}ihcro/'ti? \ X liihographica, 



"-^l.!Vthx£^ from tlie middle Oolite of Bavaria. 



among the lower Passeres, the humming-birds exceed 

 all birds in their powers of flight, and the swifts and 



