PIGEON. 127 



(b) The shaft (rachis), the solid distal part. 



2. The vane (vexillum), made up of barbs. 



3. The inferior and the superior umbilicus. 



Cut off a piece of the vexillum, socik it for a 

 few minutes in a small dish of alcohol to 

 remove the air, and examine in glycerine under 

 a high power. 

 Note the barbs, barbules, and barbicels. What 



is the relation between the barbules and 



the barbicels ? 

 Sketch, noting which is the proximal and 



which the distal side ? 



