TURTLES. 



455 



III a l'e\v cretaceous turtles found in the New Jersey grccn-sand, as well as in sev- 

 eral deposits of the same age in the West, and allied to the Testudinidie, there are 

 jiresonted ])eculiarities of structure which are so exceptional that they liave been 

 united iu a family by themselves. They are of peculiar interest to the paleontologist, 

 being generalized forms of position intermediate between the Emydidaj and Hydras- 

 pididffi. 



To the gigantic rivev-tortnise, Podocnemys exjxnisa, of the Amazon has been given 

 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 u])})er i)ortions of 

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



Fig. 2ii;i. — Hjtdra^inti maximilianii. 



during the time of dearth, the wet inontlis. Thounh tlic rich ]ieo]ile hire servants to 

 capture the animals when tlic water is low, the [loorer classes are obliged to collect 

 them themselves, as markets are unknown. Their abundaiu'e varies with the height 

 of the river, in dry seasons the largest niimbers 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 have equal advantages, 

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

 signal. 



In the family Ciiklydid.k the elongated neck cannot be withdrawn into the body, 

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



