216 



THE VERTEBRATE SKELETON. 



the marginal plates (fig. 36, 4) are twenty-three in 



FlG. 36. A, DORSAL AND B, VENTRAL VIEW OF THE CARAPACE OF A 



LOGGERHEAD TURTLE (Thalassochelys caretta), (after OWEN). 



1. nuchal plate. 6. rib. 



2. first neural plate. 7. 



3. second costal plate. 8. 



4. marginal plate. 9. 



5. pygal plate. 



thoracic vertebra. 

 first vertebral shield. 

 costal shield. 



