ANIMAL MECHANICS. 



297 



The axis PQ is drawn, in Fig. 79, at this distance from the 

 point 0; while the measured distance of the actual axis ST 

 from the point 0 is 44. 



(d.) Wong of the Macaw. — The wing of the Macaw is 

 shown in Fig. 80, where AB is the origin of the pectoral 



P 



Fig. 80. 



muscle, and A'B is its insertion. S is the centre of the 

 glenoid cavity, and A$7 7 isthe axis round which the wing-bone 

 revolves. PQ is the calculated axis, corresponding to the 

 minor axis of the ellipse (66). The angle AOB is 90 0 , which 

 I divided into parts of io° each, with the following results, 

 measured in thirty-seconds of an inch :— 



