APPENDICULAR SKELETON 1 



1. With the structural plan of the vertebrate pentadactyl limb in mind, 

 examine the mounted skeleton of a Dog or Cat and note the differences 

 between the fore limbs and the hind limbs, as well as between their respec- 

 tive girdles. 



2. Secure a detached fore limb and determine from the mounted skeleton 

 whether it is a right limb or a left limb. Identify the following bones : 

 (a) the shoulder blade (scapula) with a median ridge ; (6) the large hu- 

 merus ; (c) the radius, and (rf) ulna — the latter is the larger and forms 

 the main articulation with the humerus ; (e) the wrist (carpus), composed 

 of seven carpal bones ; (/) the hand, composed of five metacarpal bones 

 and five digits. Each of the digits consists of three bones (phalanges) 

 with the exception of the first, corresponding to our thumb, which has 

 only two. Make a reduced drawing of the entire fore limb. 



3. Secure a detached hind limb and determine from the mounted skele- 

 ton whether it is a right limb or a left limb. Identify the following bones : 



(a) the pelvis, which has a bony attachment to the vertebral column ; 



(b) the large femur ; (c) tiria, and (rf) firula — the former is the larger 

 and forms the main articulation with the femur ; (e) the ankle (tarsus), 

 composed of seven tarsal bones ; (/) the foot, composed of five meta- 

 tarsal bones, one of which is much reduced, and four digits — the first is 

 lacking — each of which consists of three bones (phalanges). Make a 

 reduced drawing of the entire hind limb. 



4. For comparison, study the limbs of a Bird, Bat, Horse, and Man. 

 Note, in all these types, the homologies of the principal bones and their 

 modifications, such as changes in form, consolidation, suppression, etc. 



•B. pp. 179-181. 



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