694 



PROP. H. Gr. SEELEY ON THE REPTILE 



sures about 4 centim. in its greatest length, and upwards of 

 3 centim. in its greatest width. The bone probably extended for- 

 ward no further than the middle of the orbit ; and in that case but a 

 small portion is lost. The area posterior to this ridge bounding the 

 back of the orbit is excavated, 4 centim. long and 2 centim. wide. 

 It consists of an inner oblong area, truncated externally by the 

 suture for the malar bone, and margined by the bevelled edge re- 

 ferred to, which is about 6 millim. wide behind and 8 millim. on the 

 inner side. The superior surface of this subquadrate fragment (fig. 8) 

 is convex from within outward, showing that the top of the head 

 was flattened, but that it rounded into the lateral area. It is divided 

 into seven areas by unusually wide and well-marked scutal grooves. 

 The bone between these grooves has a roughened, somewhat pitted 

 appearance, indicative of vascular structure. The scutes are espe- 

 cially remarkable from their number and small size ; that over the 

 orbit is largest, being about 3 centim. long and more than 1| centim. 

 wide. The other scutes will be best understood from the figure. 

 They are irregular, subquadrate or sub triangular figures, varying in 

 measurement from 1 centim. to about 1| centim. The grooves which 

 define the scutes are from 2 to 3 millim. wide. The articular sur- 

 face for the malar bone (fig. 9) is 2| centim. long, and over a centi- 

 metre deep. It is a concave shallow groove, which involves the ter- 

 mination of the postorbital ridge. There is every reason to suppose 

 that the squamosal articulation was a small area just behind the 

 malar articulation, and that it did not extend for more than a centi- 

 metre. Hence the inner and posterior bevelled articular surface, 

 which becomes very thin behind, is related to union with the parietal 

 bone. The posterior portion is oblique, and makes an angle of 45° 

 with the interior portion, which is straight and parallel to the 

 orbital margin. Three scutes are crossed by the parietal suture, 

 which, indeed, is the case in the skull of the Common Turtle. In 

 front of the parietal suture, commencing with the most anterior 

 inner scute, is a distinct suture, which prolongs the line of the 

 parietal, and therefore gave attachment to the frontal. The portion 

 of the rignt postfrontal bone includes four scutes and a fragment 

 of the inner part of the postorbital ridge, extending as far forward 

 as the termination of the parietal suture. 



Costal Plates. 



Dr. Biinzel figured a remarkable specimen, which he regarded as 

 the left ilium of an animal named Danubiosaurus anceps, the sup- 

 posed rib of which proved to be a Dinosaurian scapula. I find a 

 second specimen of this supposed ilium, less perfect, but similar in 

 character, evidently coming from the opposite side of the body. For 

 reasons to be mentioned, I have no hesitation in interpreting these 

 specimens as ribs to which dermal plates are ankylosed. But there 

 is something very different here from what is observed in ordinary 

 Chelonians ; and though I have no doubt that we have to do with 

 a pair of Chelonian costal plates, the type indicated by these re- 

 mains is new. It would, indeed, have been less startling to refer the 

 specimens to any part of the skeleton of a Dinosaur or lizard than 



