172 



half. The length of" the plastron is estimated to have been about 14 inches; 

 its breadth at the root of the posterior extremity is 5^ inches; and at the root 

 of the anterior extremity has been rather less. The sternal bridges measure 

 7 inches fore and aft, and their length to the outer edge of the carapace is 5 

 inches. 



Other measurements of the shell are as follows : 



Inches. 



Length of second vertebral scute area, estimated at 4 J 



Breadth of second vertebral scute area 3^ 



Length of third vertebral scute area 4J 



Breadth of third vertebral scute area 3i 



Length of fourth vertebral scute area Si 



Breadth of fourth vertebral scute area 3i 



Breadth of second costal scute area, internally 4| 



Breadth of second costal scute area, externally 4J 



Breadth of third costal scute area, internally 3§ 



Breadth of third costal scute area, externally 3^ 



Height of sixth and seventh marginal scute areas 2.J 



Length of hyposternals internally 5 



Breadth of hyposternals internally 5^ 



Breadth of hyosternals Sf 



Breadth of plate intercalated between the hyosternals and hyposternals G 



Extent of the same plate at the base externally, fore and aft 4f 



Breadth of groove between pectoral and abdominal areas where it joins the pro- 

 jecting angle of the third sterno-costal scute areas 7J 



Breadth of plastron at anterior suture of xiphisternals 4i 



Breadth of pectoral scutes to sterno-costal scutes 4 and 4^ 



Length of abdominal scute internally 3 



Length of femoral scute internally 3^ 



Axillary scute area, length at middle 1^ 



Axillary scute area, breadth at middle 2i 



First submarginal scute area, length at middle . . 2i 



First submarginal scute area, breadth at middle. . 2^ 



Second submarginal scute area, length at middle 2 



Second submarginal scute area, breadth at middle - 2a 



Inguinal scute area, length at middle 2f 



Inguinal scute area, breadth at middle 2^ 



The sacral vertebrae, represented in Figs. 11, 12, Plate XIX, are of pro- 

 portionately greater length than in Baena. The first one is nearly as long as 

 it is broad ; and the second is half as long again as the former, and is equal 

 ill this respect to its breadth. 



The anterior articulation of the first sacral centrum forms a decided cup- 

 like depression, and not merely a transverse concavity like that in the snap- 

 per. The second sacral centrum is prolonged to an unusual degree beyond 



