I.] THE FROG. 55 



G. The skeleton. 



The skeleton of a Frog may be prepared for exami- 

 nation by removing the viscera from the body, and 

 roughly dissecting away the muscles and other soft 

 parts. Then place the remainder in water and let 

 it macerate for about a week ; afterwards carefully 

 pick away the soft parts, with forceps, from the bones 

 and cartilages. 



Obtain two such skeletons ; allow one to dry slowly; 

 preserve the other in weak spirit. 



1. Its general arrangement. 



a. The axial skeletoii ; consisting of the vertebral 

 cohiuin and shill^ both of which lie in the same 

 antero-posterior plane. 



b. The appendicular skeleton ; lateral parts {limbs and 

 limb-girdles)^ supported, directly or indirectly, by 

 the axis. 



a. The fore-limbs : their supporting shoulder-girdle 

 or pectoral arch, not directly attached to the 

 axial column; the li7?ib proper ; its main di- 

 visions, humerus y radius and zihia (the two 

 latter ankylosed), carpus and digits. 



b. The hind-limbs : their supporting hip-girdle or 

 pelvic arch, directly attached to the vertebral 

 column ; the lit?ib proper ; its main divisions, os 



fe?noris, tibia and fibula (ankylosed), tarsus, 

 digits. 



2. The vertebral column; dried preparation. 



It consists of an anterior segmented portion (each 

 segment being a vertebra) and of a posterior unseg- 

 mented portion {the urostyle). 



