ANIMAL MECHANICS. 407 



Taking the sums of the muscles in groups, I tind the fol- 

 lowing Table : — 



Muscular Types of Man and Quadrumans — Shoulder Joint. 





Scapu- 

 lar. 



Abduc- 

 tors. 



Flexors. 



Exten- 

 sors. 



Adduc- 

 tors. 



Total 

 weight. 







Per 



Per 



Per 



Per 



Per 



Oz. av. 







cent. 



cent. 



cent. 



cent. 



cent. 



I. 



Man, . . 



24.68 



28. IO 



23- 34 



9. 80 



14.08 



77. 11 



2. 



Gorilla, . . 



24.40 



25-30 



25-45 



12. 80 



12.05 



3-32 



3- 



Chimpanzee, 



33 17 



'9-95 



22.94 



9-73 



14. 2 1 



4.01 



4- 



Hamadryas, . 



25.04 



2 1 • 55 



28.07 



10.73 



14. 61 



2.5. 80 



5- 



Cynomolgus, 



19-95 



16.94 



3'-42 



12.15 



'9-54 



7-32 



6. 



Mandrill, . . 



18.96 



20.87 



30 . 60 



•4- °7 



15-5° 



16.77 



7- 



Rhesus, . . 



20. 86 



19.96 



3 1 . 46 



11.42 



16.50 



5-5* 



8. 



Ateles, . . 



18.94 



21.93 



31.86 



14 86 



12.41 



7-34 



On examining these 'Fables, we tind in Man and the 

 Gorilla a remarkable developement of the abductor muscles, 

 due mainly to the great size of the Deltoid muscle, which 

 corresponds to the Glutceus maximus in the hip. This is evi- 

 dent from the following Table : — 



Comparison of the Deltoid Muscle in Man and the 

 Quadrumans. 





Percent- 

 age of 

 Shoulder 

 Muscles 



Relative 

 Proportion. 



Succes- 

 sive Dif- 

 ferences. 



1 . 



Man, .... 



15-32 



1 00 00 





2. 



Gorilla, . . . 



14. 02 



9' - 5 1 



8.49 



3- 



Ateles, .... 



10.34 



67.49 



32.51 



4- 



Chimpanzee, . . 



9. 00 



5* 75 



8.74 



5- 



Hamadryas, . . 



7-45 



48 63 



10. I 2 



6. 



Mandrill, . . . 



7- «5 



46.67 



1 . 96 



7- 



Rhesus, . . . 



6 . 42 



41.91 



4.76 



8. 



Cynomolgus, . . 



5-6' 



36.62 



5-29 



This Table shows that the Gorilla and Spider Monkey 

 approach nearer to Man, with regard to relative size of the 

 Deltoid muscle, than the other Quadrumans do. 



In examining the hand of Man and the Quadrumans, the 

 following well-known differences are found : — 



