450 



LOWER VERTEBRATES. 



with some distance from water and often in the dry uplands, where it crawls leisurely 

 along, stopping now and then to feed on the leaves of some favorite plant. Ou being 

 surprised it quickly withdraws itself into its shell, and might be passed unnoticed were 

 it not that it hisses so loudly. On examination the shell is seen to be composed of very 

 distinct, concentrically sculptured and brown-rayed plates; a prominent ridge being 

 formed along the back by successive longitudinal prominences. Below, the yellow 

 plastron is divided into twelve portions, each bearing on its posterior and outer corner 

 a large black blotch, around which is a series of suture-like grooves parallel with the 

 general contour of the plate. C marmoratus inhabits the Pacific regions. 



Emys is represented in North America by a single species inhabiting the more 



^^^^^■^j/luA 



Fig. 259. — Cistudo Carolina, box-tortoise. 



eastern districts from Wisconsin, and known as £1. meleagris or Blanding's box-tortoise, 

 an interesting form, as it connects the more oi-dinary members of the family — those 

 having the plastron immovably united to the carapax — with Cistudo, where it is not 

 only free, but movable at both ends in a vertical plane. The carapax of this animal is 

 strongly convex and rounded, much resembling that of the box-tortoise, though it is 

 above of a dark green color spotted with yellow. Below, the plastron is provided with 

 a longitudinal ligamentous fulcra connecting it 'with the carapax, and a single transverse 

 hinge, between the six anterior and six posterior plates, which allows, aided by the 

 fulcra, after the extremities ha'i-e been drawn beneath the carapax, of all being pro- 

 tected by the closing of the thus formed lids. Blanding's tortoise exceeds the com- 



