522 BRITISH FOSSIL REPTILES. 



bone itself, and excluding the maxillary from the boundary of the respiratory opening. 

 The application of the outer process of the fore-end of the nasal to the anterior edge ot 

 the ascending process of the maxillary could only be predicated by one mistaking a 

 crack of the premaxillary fortliesutm-e. The ascending process (lb., ib., fig. 9, 22'') vvith 

 which the nasal articulates at the outer part of its fore-end belongs to the premaxillary as 

 well as does the inner process of the same end of the nasal bone. 



The premaxillo- maxillary suture extends from behind the sixth obvious premaxillary 

 tooth for the extent of nearly an inch, with a slight curve convex forward, between the 

 two main elements of the upper jaw. The maxillary and premaxillary have been slightly 

 separated from each other along this suture by the force which has fractured both bones ; 

 but the margins of the suture show its true nature and distinguish it from the fractures, 

 especially those on the body of the premaxillary, one or other of which must be adopted 

 for a suture on the hypothesis of the hinder ascending process (22") belonging to the 

 maxillary bone. 



Of the six premaxillary teeth in place the foremost alone (lb., ib., fig. 9, i) has the crown 

 entire ; its outer surface is convex across and lengthwise, most so along the middle, trans- 

 versely, the main or mid-ridge of the Iguanodontal teeth being thus indicated. The margins 

 are also slightly relieved {Bin., PI. ,C0, fig. 18, magn.) and converge at an acute angle to a 

 sharp, slightly incurved, apex ; the enamel is minutely punctate. Neither in the right nor 

 the left deflected part of the premaxillary, anterior to the pointed tooth, is there any trace 

 of socket or fang. It would seem that this end of the premaxillaries was edentulous, like 

 the corresponding slope of the symphysial part of the mandibular rami to which it was 

 applied. The outer surface of the deflected ends of the premaxillaries is pitted and finely 

 punctate or rugose. 



The fractured bases of the premaxillary teeth succeeeding the first show a transverse 

 diameter nearly equal to the fore-and-aft one, and I can form no judgment as to the 

 shape of their missing crowns, save on the analogy of the Iguanodon. They are close- 

 set, and if those crowns extended antero-posteriorly they must have overlapped. This 

 Iguanodontal arrangement is demonstrated in the undisturbed maxillary teeth, of which 

 eight are recognisable ; the hind border of one crown overlaps the fore border of the 

 tooth behind. 



The two anterior maxillary teeth have slipped in part from their sockets and do not 

 show this arrangement. The fii'st is the smallest antero-posteriorly, but its crown has 

 been worn to the fang, and when entire would be larger in that direction. The second 

 tooth is less worn, and yields in size to the third. In the fifth the full size of the 

 crown, antero-posteriorly, is shown, and this tooth is selected for the magnified view in 

 PI. 59, fig. 10. 



The outer surface of the crown is bisected by a medial primary longitudinal ridge ; 

 behind this ridge the surface is smooth and concave transversely ; in front of the ridge 

 the similarly concave surface is accentuated l)y two low secondary longitudinal ridges. 



