74 



relative turning movements of the eyeballs. The dis- 

 charge is secured by a peculiar arrangement which 

 gives a steady appui to the ball, during the instant 

 in which the small muscles that move it, discharge 

 the twists received by them in accommodating 

 themselves to the lines of traction of the body. The 

 muscle on the inner side of each eye is made much 

 longer than the others, and instead of simply fixing 

 itself on the inner surface of the front of the eye- 

 ball socket, is there passed through a ligamentous 

 loop, in which it slips freely, and then bending at 

 a right angle, proceeds to the rear, to be fixed at 

 the back part of the socket. The counter-turns 

 received by this, the ^^ internal oblique muscle,'" are 

 discharged by its slipping in the loop, while yet 

 the eyeball is kept steadily in place by it. This 

 muscle m&y, lohen tivisted, be regarded as an S, or as 

 a rib, of which the eyeball is the foot end.^ 



§ 78. There is one more point in the anatomy of 

 the snake which it is requisite to notice in connec- 

 tion with our subject, namely, the Lungs. 



Although these organs be more imperfectly con- 

 stituted in the snake than in the higher animals, 

 they yet fulfil the function of expanding the chest 



*See§ 133 for detail. The relative action of the muscle remaining the 

 same in the higher animals as in the snake. 



