DISSECTION OF A FROG. 45 



In this preparation how many vertebrae do you find ? Can 

 you find neural and haemal arches (p. 14) ? On either side 

 of each vertebra find a transverse process. How do these 

 compare with the ribs of a fish (p. 14) ? Are they the 

 same ? Give the reasons for your conclusion. Notice the 

 long bone (urostyle) terminating the vertebral column. 

 'Connecting the hind limbs with the back-bone is the 

 pelvic arch. Is it a true girdle ? With what part of the 

 vertebral column does it join ? Connected with the fore 

 limbs is the shoulder-girdle. Does it join the vertebral 

 column ? 



Extending along the median line beiow, in connection 

 with the shoulder-girdle, is the breast-bone, or sternum. 

 How many parts in it ? Are all equally hard ? Connecting 

 the breast-bone with the shoulder are two bones on either 

 side; the anterior is the clavicle, the posterior the coracoid. 

 Extending dorsally from the shoulder-joint is the shoulder- 

 blade (scapula), and above it the supra-scapula (partly car- 

 tilage) . At the junction of coracoid and scapula is the glenoid 

 fossa, in which fits the head of the first bone (humerus) of 

 the arm. Has a joint like this much freedom of motion ? 

 The bone of the forearm is the radio-ulna. Does it show 

 any signs of a double condition ? With what does it con- 

 nect below ? How many bones in the wrist (carpus) ? How 

 are they arranged ? How many in the palm (metacarpus) 

 and in each finger ? How does the thumb differ from the 

 others ? 



On the outside of each half of the pelvic girdle is a deep 

 cup (acetabulum) , in which is the head of the thigh-bone 



then soaking the frog for weeks in water, brushing the parts every 

 few days with a tooth-brush. If such a skeleton be soaked for a few 

 days in Wickersheimer's fluid (see Appendix) and dried, it will retain 

 its flexibility and usefulness for years. 



