ANIMAL MECHANICS. 251 



the other muscles that act upon the elbow joint, into the 

 olecranon process. The right line 01 represents the di- 

 rection in which the force of this muscle is applied, and 

 it will produce its maximum mechanical effect when the 

 angle SOI becomes a right angle, in conformity with Pro- 

 position B, 



In the position of the arm shown in the figure, the angles 

 are as follows : — 



SQX = 93 0 (latiss. dorsi and teres major), 

 SOI =95° {triceps). 



The arrangement of both groups of muscles is so contrived, 

 that these angles pass through 90 0 together, thus enabling 

 both sets of muscles to act at the same moment with maxi- 

 mum effect upon the humerus. 



The triceps and its associated muscles in the Felidae have 

 the following weight : — 



Extensors of Forearm in the Felidce. 





Tiger. 



Lion. 



Jaguar 

 (female). 



Leopard. 



Triceps longus, . 



30.65 oz. 





4.20 oz. 



7.27 oz. 



Triceps internits, 



7.10 „ 





1.48 „ 



J-79 u 



Triceps extemus, 



i4-°5 „ 





1-54 „ 



3-45 „ 



Triceps aceessorius, . 



2-95 „ 





0.20 ,, 



0.67 



Anconceus, 



3-°5 





o-33 „ 



0.60 „ 



Total 



57.80 oz. 



43.50 oz 



7,75 oz. 



13.78 oz. 



If we compare these weights, which represent the work done 



