TRIONYXFEROX. 13 



velocity its long neck and head, and not unfrequently it springs upward at the 

 same time and makes a loud hiss. 



In the month of May the females seek sandy places along the banks of the 

 waters they inhabit to lay their eggs, generally about sixty in number; and it is 

 remarkable that, though their motions are slow and dithcult on dry land, yet at 

 this season they sometimes mount hillocks several feet high. 



The eggs once deposited, the female returns to the water, and leaves them to 

 be hatched by the heat of the sun. The eggs, according to Lesueur, who 

 examined them on the Wabash, are spherical, ^\ ith the shell more brittle than 

 those of the Emydes inhabiting the same waters. 



Of all the Chclonia, tlie flesh of the Trionyx ferox aflTords the most delicate 

 food, surpassing even the Green Turtle. 



Geographical Distribution. The Trionyx ferox affords an admirable illustra- 

 tion of the influence of physical geography in the distribution of animals. Thus, 

 it inhabits the Savannah as well as all those rivers that empty into the northern 

 borders of the Gulf of Mexico; it ascends up the broad Mississippi, and is found 

 in all its tributaries, even to the very foot of the Rocky Mountains, according to 

 Lewis and Clark; it abounds in the chain of the great northern lakes both above 

 and below the Falls of Niagara; and is equally common in the Mohawk, a tributary 

 of the Hudson river; but is not found in any other Atlantic stream between this 

 and the Savannah river, a distance of nearly eight hundred miles. Now a glance 

 at the map of the United States will show us how this tortoise, doubtless originally 

 a western species, and never migrating by land, can have passed by water from 

 the Great Valley of the Mississippi to the northern lakes, and to the Mohawk and 

 even Hudson river. At the source of the St. Peters' river in times of flood there 

 is a free communication with Red river of Lake Winnipeg; which thus aflTords a 

 passage for the Trionyx ferox to the Lake of the Woods. (Lat. 48°, Say, in 

 Long's Exp.) Again, the Upper Illinois is well known to communicate with the 



