PHYLOGENY. 



125 



developed among rasorial types in the sand-grouse, 

 and, among the adjacent forms, the pigeons. Then 



U^ V \_.L^J^<^VJ. Clll J^Hg 1 O.OV_H. IdJ. L_y ^J\^ ^ 11H_< 3O.11\J.' 



and, among the adjacent forms, the pigeons. 



"w. 



Fig. 32. Archceoptcryx lithographica, 

 from the middle Oolite of Bavaria. 



among the lower Passeres, the humming-birds exceed 

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



