that connect the Orders and Families of Birds. 477 



the extremes of that varied structure. With almost equal certainty 

 they reduce to the regularity of law the otherwise anomalous for- 

 mation of the Tachypetes, explaining its connexion with Hirundo, 

 and accounting for the weak and feathered legs, the forked tail, 

 the expansive wing, the powers of the long-suspended flight, 

 which give each bird the command over the element in which 

 they range in common. But I must restrain myself, or I should be 

 involved in an endless discussion of similar coincidences. It is 

 sufficient to have suggested the principles that regulate such ana- 

 logies, and the intelligent ornithologist will himself discern the 

 numberless and beautiful inferences that result from them. Pro- 

 ceed we now in order to the next succeeding department of the 

 class. 



Ord. III. RASORES. 



The two typical orders which have already come before us exhi- 

 bit the most generally perfect structure that is found among birds, 

 and consequently indicate the most extensive powers, and the 

 widest sphere of action. The strength and perfect developement 

 of their wings confer on them the faculty of locomotion to the 

 fullest extent; while the structure of their foot affords them equal 

 facility in grasping their prey, in walking, climbing, and perch- 

 ing. They thus extend their dominion over nature almost 

 without any apparent limits. The different elements seem alike 

 subservient to their purposes : on land, they form their habita- 

 tions and obtain their food in the forest, on the plain, and the 

 mountain ; they pursue their prey through the tracts of air, and 

 are not debarred even from the waters. Pursuing the same line 

 of inquiry among the aberrant groups of the class, we may 

 observe their powers which depend on conformation becoming 

 more circumscribed, and their sphere of life brought conse- 



3 Q 2 quently 



