95 



§ 93. While the action of the ophidian and com- 

 posite S S tighten the right corner of the sternum, 

 and the right fore-leg against the left hind-leg, a 

 little additional motion of the head-joint tightens the 

 left sterno-mastoid, and thus produces the " bicompo- 

 site /S"' (§ 84). The bracing of the composite and 

 ophidian S S is diagonal, that of the bicomposite is 

 collateral. 



§ 94. In this gathering movement the front appui 

 (here the right fore leg) goes tvifh the body, and, as 

 we shall see, the free fore-limb (here the left) prin- 

 cipally and finally tuith the neck. 



§ 95. Each motion of the head condyles affects 

 the sternum through the medium of the neck S, but 

 its more immediate action, through the sterno-mas- 

 toids, so du'ectly affects this bone, that if a head con- 

 dyle (not an anterior point of application, at the front 

 of the chest, and, thus the " bicomposite," not the 

 opHdian S) begins the gathering, it will cause the 

 sternum to move before the spine, a circumstance 

 which, as we shall see further on, may explain 

 those movements of the limbs— the pace, &c. — 

 which do not seem to be strictly diagonal. 



§ 96. In attempting to follow out the effects of 

 the head condyle movements on the sterno-mastoid 



