356 



ANIMAL MECHANICS. 



Distance of 0 from centre of socket = 1.82 in. 

 Distance of 0'from centre of socket = 2.32 „ 



Difference, . . . 0.50 in. 



The points 0 and 0' are both inside the origin and insertion, 

 but the point 0' is only 0.41 in. inside the posterior end of 

 the insertion, showing, as in all the former cases, that the 

 equivalent fibre is inserted very high up on the femur. 



5. African Leopard — Adductor secundus (a). — I shall se- 

 lect, as my last example of skew muscles, the ischiadic sheet 

 of the second adductor of the African Leopard. In this case, 

 the shortest fibres are the most posterior fibres on the ischium, 

 and are inserted highest up on the femur : this difference of 

 arrangement will require a change of sign in some of the 

 quantities used in my calculation, which will be readily un- 

 derstood from the formulae employed. 



African Leopard — Adductor secundus (a). 



Lengths of Origin and 

 Lengths of Fibres. Insertion. 



p = 3.55 in. a = 1.66 in. 



Pi = 4-24 „ a* = 5-4o „ 



p 2 = 6.42 „ 



Constants of Hyperboloid. 

 2C = 2.26 in. 

 20 = 74°40 / . 



The positions of the points I and I' were found by combining 

 the lengths of the fibres, in pairs, as in the following 

 equation : — 



p- 2 - p 2 = 2 {a - a' cos 2<p) a 

 + 2 [a- - a cos 20) a' 

 + [a 2 J rji' % - 'iaa' cos 20 J. 



