62 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. i. 



On the other hand, a study of the figures of the parts of the 

 skull on plates X and XI of the work cited renders it highly probable 

 that the bone figured on plate X as the maxillary is not such, but the 

 postfrontal; while the figure on plate XI, said to represent the post- 

 frontal, really portrays the maxillary, prefrontal, vomer, and pala- 

 tine. In such case, the length of the skull would be about a fourth 

 greater, or 40 cm. 



The length of the carapace of Chelonia has a ratio to the plastron 

 of about 31 to 24. Hence the length of the carapace of my specimen 

 must have been close to 3. i metres. The neck of our living marine 

 turtles projects beyond the front of the carapace a distance equal to 

 at least one-sixth of the length of the carapace. Hence, we are safe 

 in allowing 50 cm. for the neck outside of the shell. We have there- 

 fore for the length of this turtle the following figures : 



Head 32 metres. 



Neck beyond carapace 50 



Carapace 3.10 



Total 3.92 metres. 



