434 OLIVER p. HAY 



the hinder edge of the shell, it is judged that the animal had 

 been kept in captivity before it was brought to this country. 

 The length of the carapace is 400 mm. After maceration and 

 cleaning, an examination has been made of the shell. On the 

 carapace not as many of the scute areas have furnished epithe- 

 cal bones at the centers of growth of the scutes as was hoped. 

 Nevertheless, a thin cap of bone was found on the rear of the 

 third vertebral scute and a small bone at the rear of the second 

 right marginal scute and another on the left. Distinct evidence 

 of similar bones occurs at other points where they might be ex- 

 pected to occur. On the plastron there is a scar on the right 

 side of the front edge of the intergular where there may have 

 been a plate of bone. On nearly the whole of the front of the 

 right gular there is a surface (a) from which a bone was cer- 

 tainly lost during maceration. No plates of bones are found on 

 the outer hinder angles of the humeral scute areas. On- the 

 outer hinder angle of the plastral portion of each of the pectoral 

 (b) and the abdominal (c) scutes of both sides is found a large 

 patch of thin bone. All of these bones give evidence of more or 

 less absorption and removal. On the outer border of each fem- 

 oral scute area, at about its middle, is a thin bone (d) 30 or 

 more mm. long. This appears to correspond to the anterior of 

 the two bones found on the femoral areas of the specimen shown 

 on plate 1. The hinder one had probably long before been 

 absorbed. On the anal scute areas no similar bones are present, 

 but a scar (c) on the one of the left side may indicate the former 

 existence of a plate. 



The most conspicuous feature of this shell is the numerous 

 smaller plates scattered irregularly all over the surface of both 

 the upper and the lower sides. Figure 8 shows some of these 

 of nearly the natural size on the left side of the first vertebral 

 scute area and on parts of the adjoining scutes. Here the little 

 bones are yet present, each in a depression in the costal bone. 

 Nearly all of these bones are polygonal. All over the shell are 

 presented areas where there were evidently once little flakes of 

 bone, but these are now gone, only little pock-like scars remain- 

 ing. The figure of the plastron shows the number and size of 



