TURTLES. 



455 



In a few cretaceous turtles found in the New Jersey grecn-saiul, as well as in sev- 

 eral deposits of the same age in the West, aiul allied to tlie Testudinidw, tliere are 

 presented peculiarities of structure which are so exceptional tliat they have been 

 uhitod in a family by themselves. They are of peculiar interest to the paleontologist, 

 being generalized forms of position intermediate between the Emydidie and Ilydras- 

 pididiE. 



To the gigantic river-tortoise, Podocncmys expansa, of the Amazon has been "iven 

 a family value. It is of an enormous size, and is a load for the strongest native, the 

 shell, when full grown, measuring nearly three feet in length. In the upper portions of 

 the Amazon every household has a pond or corral, in which the animals are confined 



during the time of dearth, the wet months. Though the rich people hire servants to 

 capture the animals when the water is low, the poorer classes arc obliged to collect 

 them themselves, as markets are unknown. Their abundance varies with the height 

 of the river, in dry seasons the largest numbers being captured. The flesh is very 

 tender, palatable, and wholesome, though one soon tires of it as a regular diet. The 

 eggs are eagerly sought after by the natives, and, that all may liave equal advantages, 

 the excursions to the sandy islands are made in a body, all setting to work at a given 

 signal. 



In the family Chelyuid.e the elongated neck cannot be withdrawn into tlie body, 

 as in the ordinary forms, but protection is obtained by bending it round against the 



