224 THE BIOLOGY OF THE AHIMAL 



Eemove the levator bulbi and look for 



Tc. The recti muscles, four small muscles arising 

 together from the inner posterior angle of the 

 eye-socket. 



I. The obliqui muscles, two muscles arising from 

 the anterior end of the eye-socket. 



m. The retractor bulbi, a cone-shape muscle, aris- 

 ing from the angle of the parasphenoid. "What is 

 the function of this muscle? 



Make a list of the muscles which (1) raise or 

 protrude the eyeball ; (2) depress or lower it ; (3) 

 rotate it in the socket. 



III. Muscles of the front liimh. 



a. The sternoradialis, a triangular muscle lying in 

 front of the shoulder-joint. To what muscle in 

 the human body does it correspond ? 



5. The deltoid, a narrow muscle lying in front of 

 the sternoradialis. 



c. The triceps brachii, on the upper surface of the 

 arm. 



d. The flexor muscles of the forearm and digits, 

 covering the inner side of the antebrachium and 

 lower surface of the manus. 



e. The extensor m.uscles of the forearm and dig- 

 its, lying on the outer side of the former and 

 upper surface of the latter. 



Which of these muscles will draw the arm 

 forward? Which bend it? Which straighten it? 

 What relation has the deltoid ridge of the hu- 

 merus to the attachment of muscles ? 



