CHELONIA^J REPTILES. 419 



gular inversion in the position of the scapida ; for 

 it is here placed on the inside of the ribs and 

 sternum ; that is, between the carapace and plas- 

 tron.* The humerus is remarkably curved, espe- 

 cially in the tortoise, where it has the form nearly 

 of a semi-circle. The radius and ulna are distinct 

 from each other: the carpus and phalanges are 

 short and stunted, forming a compressed kind of 

 hand. 



The pelvis, like the scapula and clavicle, is en- 

 closed within the bony shell which protects the 

 trunk. The sacrum is moveable upon the last 

 dorsal vertebra ; and the coccygeal vertebrae are 

 continued from it, forming a short tail. The femur 

 is short and powerful, and somewhat bent, but less 

 so than the humerus ; and the rest of the bones of 

 the hind extremity are similar to those of the fore 

 leg.'}" All the feet are joined obliquely to the limbs 

 which support them, giving the animal an apparent 

 awkwardness of gait, as if it were obliged to walk 

 upon club feet. The impulse which they give, 

 being lateral and oblique, renders them more effi- 

 cacious for progression in the water than on land : 

 this circumstance, in conjunction with the consti- 

 tutional torpor of the animal, sufficiently accounts 



* The anomalous situation of these bones, and the strangely dis- 

 guised forms which their several parts assume, render it very diffi- 

 cult to recognise in the skeleton the several pieces which correspond 

 to the normal type of the scapula, acromion, coracoid bone, and 

 clavicle ; and anatomists are not yet agreed as to the proper desig- 

 nations vvhich are applicable to these bones in the Chelonia. 



t The cylindrical bones of the tortoise are solid throughout, and 

 have no cavity for containing marrow, as in the more highly de- 

 veloped bones of the mammalia. This is seen in the section of the 

 femur. Fig. 214. 



