ANIMAL MKCHAN10S. Odd 



carefully placed the thigh in the position of extreme abduction, 

 I made the following measurements : — 



Llama. 



Lengths of origin and insertion. 

 a = 1.96 in. (origin). 

 a' = 6.00 insertion. 



Constants of Hyperboloid. 

 2c = 2.38 in. 

 2tf> = 4V°i5' 



The constants of the Hyperboloid were measured by 

 fastening straight steel wires along the directions of origin and 

 insertion, and then measuring the shortest distance between 

 them, and the angle made by the two lines. 



The positions of the points 1 and T, on the bones, may 

 either be measured directly, like 2c and 20, or may be calcu- 

 lated from the other measurements. In order to check the 

 whole calculation, I measured their position, and found 



a = + 1.96 in. 

 a' = + 4.40 ,, ; 



where a signifies the distance from I to the (anterior) fibre p, 

 measured on the bone AB ; and a signifies the distance from 

 /' to the same (posterior) fibre p, measured on the bone A!B ' . 

 It is to be noted that the fibre p is anterior on the pubes, and 

 posterior on the femur ; so that all the fibres cross each other, 

 forming a well marked skew surface. The values of a and a 

 may be calculated as follows, from the measured lengths of 

 any two fibres (p. p 3 ) — 



p 2 = a 2 + a''' - 2aa' cos 2</> + 4c 2 , 



pi = (a - aj + (a + a) 2 - 2 (a - a) (a + a') cos 2<p + 4c 2 ; 



Lengths of equidistant fibres. 

 p = 4.27 in. 

 P\ = 6.70 „ 

 p 2 = 8.46 „ 



Pz = IO.80 „ 



