TRIONYX FEROX. 



15 



velocity his long neck and head, and not unfrequently 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 difficult 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, with the shell more brittle than 

 those of the Emydes inhabiting the same waters. 



Of all the Cheloniadse, the flesh of the Trionyx ferox affords the most delicate 

 food, surpassing that even of the Green Turtle. 



Geographical Distribution. The Trionyx ferox affords an admirable illus- 

 tration 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 great northern lakes 

 both above and below the Falls of Niagara; and is "common" in the Mohawk, a 

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

 between that 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 loater from the Great Valley of the Mississippi to the northern lakes, 

 and to the Mohawk and even Hudson river. At the source of St. Peter's river in 

 times of flood there is a free communication with Red river of Lake Winnipeg, 

 (lat. 48°, Say, in Long's Exp.;) which thus aflbrds a passage for the Trionyx 

 ferox to the Lake of the Woods. Again, the Upper Illinois is well known to 



