24 CHELONURASERPENTINA. 



teriorly. The gular plate is single, and of rhomboid form, rounded in front and 

 pointed behind, where it is received between the brachial, which are elongated 

 and triangular, with their apices forward and truncate. The thoracic plates are 

 largest of all, and are very regularly pentagonal, with their posterior and external 

 border shortest where they join the abdominal plate, which is irregular in form 

 as well as in position; they are shaped somewhat like an hour-glass, broader 

 internally, where are two articulating facets for junction with the thoracic and 

 femoral plates; they are narrow in the middle, and again expand at the wings to 

 join with two supplemental plates; the femoral are similar to the thoracic in 

 form, but are smaller and narrower on their anterior and external border, where 

 they unite with the abdominal plates; the subcaudals have the form of regular 

 isoceles triangles, with their bases forward and their apices backward. There are 

 three supplementary plates at the wings; the inguinal is broad, very irregularly 

 four-sided, with its posterior and external angle greatly prolonged; the axillary is 

 also broad, and is regularly quadrilateral: these two unite the abdominal plate 

 with the marginals by means of a cartilaginous substance. The third supple- 

 mentary plate is situated in front of the axillary; it is long, narrow and pointed 

 anteriorly, but is in no way connected with the abdominal plates. 



The head is very large, yet the animal can draw it under the caparace; it is 

 broad behind and flattened above, with the snout short, though pointed, covered 

 posteriorly with warty integuments, and anteriorly with the same and occasional 

 small plates at the sides, all adhering firmly to the cranium. The nostrils are 

 anterior and near together. The eyes are large, prominent, and placed near the 

 snout; the pupil is dusky, the iris grey, with a few specks of yellow. The upper 

 jaw is strong, with a sharp cutting edge and a well developed hook in front, on 

 each side of which is a depression or notch. The lower jaw is equally firm, with 

 a similar cutting edge, an equally well developed hook in front, and is received 

 within the upper. The neck is long, but thick, and covered both above and 

 below with a granulated or warty skin, and occasional warts of larger size, two 

 of which, at the chin, are of great length, like barbels. 



