TAB. XIIL4. 



Chelone crassicostata. 



Portion of the carapace, half the nat. size, with the corresponding series of marginal 

 plates, me — m\2, and py. 



ph and ph, the third and fourth costal plates of the left side ; ph — ph, impres- 

 sions in the matrix of the succeeding costal plates. 



