402 



ANIMAL MECHANICS. 



2°. The complete separation of the iliacus and psoas 

 magnits. 



3 0 . The separation of Gluteus secundus (a) and (j3). 



4°. The absence of Glutceus quartus. 



5°. The perfect differentiation of the adductors. 



The broad differences in type will be best seen from the 

 following Table, in which the muscles are arranged in group? 

 as before : — 



Muscular Types of Man and the Quadrumans — Hip 

 Joint. 



Animal. 



Abductors. 



Flexors. 



Extensors. 



Adductors. 



Total 

 weight. 







Per ceiiu 



Per ceix, . 



Per cent. 



Per cent. 



O'a. av. 



I. 



Man, .... 



39 6 7 



18. 21 



16.68 



25 - 44 



93- 17 



2. 



Gorilla, 



33 o4 



13. 12 



24. 12 



29.72 



2.86 



3- 



Chimpanzee, . 



32.50 



17.92 



20.83 



28.75 



2.40 



4- 



Hamadryas, . . 



26. 42 



18 . OO 



34-59 



20.99 



24.34 



5- 



Cynomolgus, . . 



22 . 90 



18.62 



31.45 



27.03 



7-25 



6. 



Mandrill, . . . 



22.77 



14.99 



34-72 



27.52 



17 48 



7- 



Rhesus, . . . 



22. 24 



17. 66 



32. 62 



27.48 



18. 12 



8. 



Ateles, . . . . 



20. 84 



2 1 . 60 



25.79 



3 1 - 77 



7.87 



In this Table, it will be observed that the flexors and 

 adductors are much alike, and that man's superiority consists 

 in the increase of the abductors at the expense of the ex- 

 tensors. This is mainly due to the developement of the Glu- 

 tceus primus, which is essential to man's erect posture ; and 

 to the diminution of the biceps femoris, which is essentially a 

 brute or quadrupedal muscle. 



Taking together the Glutceus primus and tensor vaginas 

 femoris, we obtain the following instructive comparison : — 



