154 



THE EXTINCT BATRACIIIA, EEPTILIA 



The ossification of the disc is perhaps more extensive than in C. mydas, if the small size of the extremities of 

 the ribs bo indication. They are very flat in both directions. The surface is smooth, or with only 11 10 vascular 

 grooves found in the species of the family generally. A nucha] or marginal vertebral is partially preserved, having 

 lost; the posterior portion. The margin is heavy, thinner than as usual medially, and with a little irregularity whore 

 the dermal scutum crosses. The suture with the first marginal is nearly straight, except that the latter sends a flat 

 process a considerable distance over the posterior face of the former. 



The right scapula and part of the procoracoid are preserved. These have the extensive union characteristic of 

 Chelonc, and the short coracoid suture. The scapula is flattened so as to be antero-postcrior above, transverse below. 

 The procoracoid is strongly compressed to a vertical section. The head and great trochanter of the femur are pre- 

 served. These also present the characters of Chelonc. The little trochanter is on the shaft some distance below tho 

 head. All but its base is lost;. The great trochanter is higher than the head, and is a plane at right angles to the 

 plane of the latter. Its extremity is conic, and its connecting portion contracted and descending below the line of 

 the head. 



Width of costal bone, 



Thickness " at suture, 



" of nuchal bono at marginal suture, 



Length nock seapulo-procoracoid, 



Width " 



Length coracoid suture, 



Depth procoracoid at middle, 



Length scapula to infer, side, 



Width " extremity, 



Transverse diameter shaft femur, 



Diameter shaft and great trochanter, 

 The accompanying cuts show the forms of the head of the femur and of the scapula. 



Another specimen in the museum of the Academy, from the same locality, exhibits the characters of four margi- 

 nal bones and a fragment of one of the hyostcrnals. In general character's the middle and posterior of tho former are 



Lines. 

 39.5 

 G. 



0. 



4i 



18. 



18. 



10. 



38. 



20. 



22.8 



45.8 



Fig. 41. 



Fig. 40. 



e 



like those of Propleura; tho anterior presents the characteristic slenderness seen in Chelone. One end of the latter 

 is broken; the remainder measures four inches in length, 22.5 lines in width, and only 10.5 lines in depth medially, 

 being flat and thin. The outer margin is flat and entire. Tho inner presents two shallow pits at its posterior part, 

 close together, the hinder partly on the suture with the adjoining marginal, and directed a little forwards; the an- 

 terior directed backwards. As this is probably tho anterior rib-bearing, or third marginal, it looks probable that 



