50 



ances of the spine, with which the ribs articulate, 

 the ribs will be thrown more or less upon the outer 

 or the inner edge of their ground ends, and, being 

 bent against the ground on one edge, the introduc- 

 tion of a counter-turn, though this be only poten- 

 tial and latent as regards the spine, will yet bring 

 the bearing of the ribs on the contrary edge, to 

 that on which they at first rested. 



We believe that two bevels — an inner and an 

 outer — are found on the ground ends of the snake's 

 ribs ; but, however this may be, the change from 

 outer to inner side (or vice versa) of the feet which 

 furnish the appuis on the ground in the higher animals 

 is a marlzed feature of their locomotion, and we may 

 observe a no less marked distinction in the succes- 

 sive application of the two sides of the palm of the 

 hand in man, when this member is perfectly used. 



We shall often employ the terms innner and outer 

 hearings (or levels when speaking of the edges of 

 the ground ends of the snake's ribs, and also of the 

 two sides of the feet in quadrupeds, and of the 

 feet and hands in man. 



§ 52. It will be noticed that, in the snake, the 

 helices of the spine appear from the extreme 

 pliableness of the ribs, to be more or less flattened, 

 so that the body seems to move chiefly by curva- 



