360 AMERICAN TESTUDINATA. Part II. 



of the hind feet, and over the heel, and a httle way above the back surface of 

 the hips, and the space intervening between them, and over the upper surface 

 of the tail. 



The size in this fixmily is greater than in any other of the sub-order. The 

 Gallapago Tui'tle, Cylindrapis indica, may be rated at about three feet, the African 

 Coui, Psammobates radiatus, at eighteen inches, the South American Chelonoides 

 tabulata at fifteen, our Gopher, Xerobates carolinus, at twelve, and the common 

 European land Turtle, Testudo gra^ca, at eight inches in length. Thus they are 

 all comparatively large, — except the European species, which is the smallest of the 

 whole family, — and, on the whole, by no means as small as some of the Emy- 

 doidaj ; but the great height and fulness of the body make the relative size still 

 much larger than the comparison of their length alone would indicate. 



This family live entirely on dry land ; and when placed in the water, they 

 try to walk as if on land, having no true swimming motion. In walking, they 

 carry the body high up from the ground ; the legs are not spread so far apart, 

 and move in a plane more nearly perpendicular, than in the Emydoidae ; more- 

 over, as the hands are fixed in the jjlane of the forearm, the body is raised 

 up on the ends of the fingers, or at least upon the last joints ; the hind legs 

 rest indeed upon the whole lower surface of the foot but the knee joint, when 

 the foot is first brought to the ground, is open to about a right angle, and the 

 foreleg, which is always long, is nearly perpendicular, so that this end of the body is 

 raised to about the same height as the other. They walk with a firmer and more 

 steady gait, and travel for a distance with greater rapidity, or rather less sloAvly, 

 than any other Turtles. The front leg is carried forward, and the sharp, spade-like 

 nails being fixed to the ground, the body is pulled toward it, the elbow joint closing, 

 and the forearm and humerus approaching one another. The deltoid muscles, which 

 do the most in pulling the body forward, are here very largely developed. The 

 hind leg is carried round to the side of the jielvis, so that the humerus, then 

 nearly horizontal, reaches almost directly forward ; the knee is bent to about a 

 right angle, and the whole lower surfiice of the foot, with the nails, rests upon 

 the ground ; then as the body is pushed forward, the angle of the knee-joint 

 opens, and the leg straightens out. The simultaneous opening of the knee and 

 closing of the elbow keep the body, while moving, steady on one plane, and 

 there is here a regularity in the walking motion far beyond that of any other 

 family of Testudinata. 



The animal has nothing of the ferocious dispositions of most other families ; 

 it always retreats from attack, and will not bite, even when pushed to extremity ; 

 it first seeks some hiding-place, but if it is hindered in this, and the danger is 

 close at hand, it resoi'ts to its shield, and trusts solely to it for protection. The 



