BIRDS 



1588 



relations, the reptiles, and from mammals, the fol- 

 lowing may be noticed: 



But those contrasts are only a few of the less tech- 

 nical selected from Professor Huxley's masterly com- 

 parison of the three classes. To appreciate the full 

 extent of the resemblances and differences between 

 birds and reptiles, and the contrast between both and 

 mammals, the reader must consult Huxley's Anat- 

 omy of Vertebrate Animals. 



Most birds use their wings in flight, the feather- 

 covered arms being raised and depressed with great 

 rapidity by means of the breast muscles. Every one 

 who has watched birds is familiar with the marked 

 differences in rapidity and mode of flight. It has 

 been calculated that a common average of rapidity 

 is about 40 to 60 feet per second, but records of the 

 feats of carrier-pigeons, etc., certainly greatly sur- 

 pass this. It seems probable that strong-winged 

 birds, like eagles, can cover about 80 feet in a second. 

 Buffon noted that they disappeared from sight in 

 about three minutes. Strong birds, like* the alba- 

 tross and birds of prey, can not fly very rapidly, but 

 can sustain their exertions for long periods, while 

 many other birds rarely take prolonged flights, ex- 

 cept during migration. The ostrich uses its wings to 



