Practicum I. The Clavicle. 9 



of the cut as in PI. IV. To expose it more fully evert the muscles, tear- 

 ing the connective tissue. When the clavicle is found tear and cut it 

 from the muscles. Scrape clean with a dull edge. Note the slight curv- 

 ature of its ends in opposite directions, and that the lateral or scapular 

 end is the wider. 



a. In man and some other animals the clavicle is firmly connected with the sternum 

 at one end and at the other with the scapula (shoulder-blade), and thus serves to brace 

 the arm away from the trunk. In the cat the attachments are loose ; in the dog it is an 

 insignificant ossicle ; in the horse, cow, sheep, etc., it is altogether absent. 



b. The cleaned and dried clavicle of the cat is entirely inoffensive and may be pre- 

 served or even carried in the vest pocket as a good example of the organs which are appar- 

 ently functionless and are hence called atelic. 



19. Transect the other pectorals and axillary parts Cut the cords 

 that hold the arms to the tray. Turn the cat so that it rests on the ven- 

 trum. Note the wide muscle converging from the ribs to the vertebral 

 margin of the scapula. Together these muscles support the trunk between 

 the arms somewhat as would a broad sling. 



20. Divide these muscles and any other parts and detach the arms. 

 Tie them and the right leg together with a tag bearing the name of the 

 student, the number of his Practicum Section (I, II, III or IV) and the 

 number of his seat (i, 2, 3 etc.). 



