REMAINS OF REPTILES AND FISHES. 83 



wide, flat, thin, squamous process, probably for the articulation 

 of the maxilla. The opposite margin is not perfect ; but in a 

 smaller specimen of the same bone a similar flat articular process 

 extends from the upper margin also. 



The bone which we suppose to be the posterior portion of a 

 mandibular ramus is nearly five inches in length and 1^ inches 

 wide, including the lateral squam^ous expansions ; it is thin, flat, 

 and rounded in front ; behind it is much thicker. And though 

 the posterior extremity is wanting, the greater portion of the 

 articular process is jpresent ; it has a wide oblique glenoidal sur- 

 face. The lateral squamous expansions will undoubtedly articu- 

 late with the dentigerous bone. 



Other interesting bones have also occurred, some of which can 

 be identified as jugulars. One distorted and folded mass com- 

 prises two large jugulars, apparently the pair of principal plates. 

 A considerable portion of one of them is well displayed, exhibit- 

 ing in very good condition the surface ornament. Were this 

 jplate unfolded it would be about seven inches long and 2| inches 

 wide. Three or four inches of what seems to be the posterior 

 portion lies flat upon the matrix, and shows the contour quite 

 perfectly. The plate is apparently equally thin throughout ; and 

 the outer margin seems, judging from the portion that is dis- 

 played, to be pretty regularly arched, and the porterior margin 

 to be rounded and sloped a little forwards towards the inner 

 border. 



Another bone, probably also a jugular, is worthy of notice. 

 This appears to be an anterior plate ; nearly one-half of it can 

 be made out: it is symmetrical, having a stout angular midrib 

 with two lateral wing-like expansions. When entire it would be 

 4^ inches wide, and 1-| inches long. It is impossible to over- 

 look the resemblance of this bone to the jugular plate of Astero- 

 lepis ; and, like it, this probably fitted into the top of the arch 

 formed by the junction of the mandibular rami. In Bhizodus, 

 however, there appear to be two other plates, as we have already 

 seen ; these would lie one on each side of the median line, im- 

 mediately behind the anterior plate, which is very nearly as wide 

 as the two others put together. 



