= 
og 
PLATE 22. 
Chelone crassicostata. 
. Portion of the plastron seen from the under side. 
As. 'The hyosternal; ps, the hyposternal; as, the xiphisternal. 52 is the 
coracoid, exposed by the removal of the right hyosternal. 
Cast in the matrix of a portion of the carapace of the same individual, showing 
the characteristic thickness of the ribs, p/, pl. 
