88o 



LIFE : OUTLINES OF GENERAL BIOLOGY 



"The reptile seems the very opposite to all this. Sluggish and slow 

 it creeps along; it requires sunshine and warmth to stimulate it to 

 action; cold paralyses its every movement. The body is covered with 

 scales, or marled with scutes, and its four limbs are all used in its 



QW 



Fig. 152. 



Structure of a Typical Feather. From a specimen. lU, inferior umbilicus, 

 where pulp enters; C, calamus or quill; AS, aftershaft; R, rachis or 

 axis of feather; OW, outer half of vane; IW, inner half of vane. The 

 vane consists of numerous barbs united by barbules and barbicels. 



progress along the ground. The fore-hmb has no resemblance to the 

 bird's wing, and the jaws are usually toothed." 



Yet in spite of these deep differences, no competent inquirer, 

 especially since Huxley's clear anatomical comparison and yet 

 co-ordination, doubts that birds sprang from reptiles! Before we 

 consider the reasons for this, it may be of use to point out that the 



