i6 REPTILES AND BATRACHIANS 



thick neck, strongly hooked jaws, a long tail, a chin provided 

 with fleshy appendages, and a very small cross-shaped 

 plastron. Chelydra serpentina reaches a total length of 

 about three feet, Macrodemmys to almost twice that size. 

 The tail accounts for more than a quarter of the total 

 length. The colour in all species is dull olive above, 

 yellow inferiorly. 



Chelydra serpentina is distributed throughout the 

 United States and extends into Mexico, while Macrodem- 

 mys, although occasionally found in the Southern States, 

 is most abundant in the Mississippi and its tributaries. 

 The second species of Chelydra, Ch. rossignoni, which is 

 rather rare, is found in Central America and Ecuador. 



In Macrodemmys a number of white fleshy appendages 

 of the mucous membrane are situated just in front of the 

 tongue, which, the mouth of the creature being kept 

 open, when in the water, are moved in such a manner as 

 to simulate living worms, with the evident object of 

 attracting the fish it lives on. 



All these turtles are notorious on account of their 

 savage dispositions. When annoyed they elevate them- 

 selves on their hind limbs and turn almost complete 

 somersaults in their efforts to bite. According to Holbrook 

 they live at the bottom of stagnant pools or rivers of 

 sluggish motion, occasionally coming to the surface with 

 the tip of their snouts elevated, the other parts concealed, 

 and in this manner float about aimlessly, descending to 

 the bottom again when disturbed. They are occasionally 

 said to leave the rivers and to roam about on land, some 

 distance from the water. They are much esteemed as 

 an article of food, and large quantities, at least in North 



