450 



LOWER VERTEBRATES. 



■with some distance from water and often in tlie dry uplands, wliere it crawls leisurely 

 alono-, stopping now and then to feed on the leaves of some favorite plant. On 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 verj' 

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

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

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

 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. 



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



:>cr^^,:^. 



'^^^^^^j;^u/^^^ 



Uu"^^- 



Fig. 259. — C«5(«(/o Carolina, box-torloise. 



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

 an interesting form, as it connects the more ordinary members of the family — those 

 having the plastron immovably united to tlie 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 jilatos, which allows, aided by the 

 fulcra, after the extremities have been drawn beneath the carapax, of all being pro- 

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



