CHELONIA CARETTA. 45 



four principal supplemental plates, the anterior of which is small, and does not 

 reach the sternum; the three others are very large; the second is pentagonal, 

 and joins the thoracic; the third is quadrilateral, and unites with the abdominal; 

 the fourth is trapezoid, and is connected both with the abdominal and femoral 

 plates; besides these there are some smaller plates that border the brachials and 

 thoracics; the two larger of which connect the second supplementary wath the 

 anterior border of the thoracic, but none reach the shell. 



The head is extremely large, broad behind, rather rounded in front, and covered 

 above with about twenty polygonal plates of various sizes. The vertical is small 

 and hexagonal; on each side it has the superior orbitals, which are elongated pen- 

 tagonal and broadest within; behind these are the posterior superior orbitals, one 

 on each side, of similar form but larger without; behind these again, and on the 

 same longitudinal line, are the parietal plates, of irregular pentagonal form; in the 

 midst of all these plates, and united to all, is a large broad occipital plate, having 

 two or three small plates on its posterior border. There are three posterior orbi- 

 tals; the superior of which is pentagonal and large, the middle is hexagonal and 

 nearly of the same size; the inferior is largest of all, oblong, and makes part of 

 the inferior wall of the orbit; behind these plates are four longitudinal rows of 

 temporal plates, varying in size and number; the frontals are large and pentagonal, 

 the nasals are small and hexagonal, wath a narrow elongated trapezoid internasal 

 plate, which is continued back between the anterior part of the frontals. The 

 upper jaw is protected by a thick horny covering, rounded in front and broad, 

 narrow behind and reaching under the orbit of the eye. The nostrils are anterior, 

 near together, and placed in a cartilaginous substance that occupies the space 

 between the nasal plates and the horny covering of the upper jaw. The eyes are 

 large and prominent; the lids are covered with small plates, and open obliquely 

 from behind downward and forward; the pupil is deep sea-blue, with a dusky grey 

 iris. The upper jaw is strong, nearly a straight line, being but slightly bent 

 downwards in front; the lower jaw is equally firm and strong, and is more or less 

 hooked or turned upwards in front. The neck is short, very thick and strong. 



