1040 
MR. J. W. HULKE ON THE OSTEOLOGY 
In the fragment of a skull in.Mr. Fox’s collection, in which it is but little damaged 
and has retained its natural relations almost undisturbed, the length of the quadrate 
is 53 millims.; its antero-posterior dimension just below the squamosal end is 6 millims.; 
at the distance of 21 millims. from this end it is 10 millims ; and just above the 
mandibular end it is 5 millims. (the length of the portion of mandible preserved which 
comprises the entire dentigerous and part of the edentulous spout, given for con- 
parison, is 96 millims.). The width or transverse diameter of the quadrate near its 
mandibular end in a smaller mandible is 10 millims. The squamosal articulation of 
the quadrate was described in connexion with the former bone. 
Mandible (Plate 71, figs. 3, 4; Plate 72, figs. 1, 2; and Plate 73).—This repeats in 
miniature that of Iguanodon Mantelli. It has a spout-like symphysial end (Plate 72, 
fig- 2); great depth of the dentigerous part; a high coronoid process from which the upper 
border falls abruptly to the quadrate joint, and slopes gradually towards the junction of 
the tooth-bearing and edentulous parts. The lower border is almost straight. The 
articular element is large, and the joint-surface very capacious relatively to the size of 
the lower end of the quadrate , an arrangement which would have permitted a very free 
movement of the mandible upon the quadrate. The angular element appears to be 
small, it reaches to the posterior extremity of the mandible. A splenial plate covered 
the large subdentinal groove. 
In a slab in my collection immediately in front of a much-crushed mandible is a 
thin triangular bone symmetrically bent into a trough-like form appearing not unlike 
a continuation of the symphysial mandibular spout, one edge of the triangular bone 
having the same slant as the inclined border of this. 
I do not identify this bone with the mandible. The close proximity of a prse- 
maxillary tooth to it suggests that it may be connected with the prsemaxilla. I 
mention it in order to call attention to it. 
Under surface of skull. —This is described entirely from my skull No. 110, as this 
region in Mr. Fox’s type skull appears to me too damaged to afford unequivocal 
evidence of the nature of the pieces of bone displayed and of their relations. 
The palate is closed in front by the junction in the middle line of the triangular, 
prmmaxillary, palatal processes (Plate 72, fig. 1). A small anterior palatine foramen is 
situated in the front of the palatal inter-prsemaxillary suture. The posterior borders 
of these processes curve inwards, and, meeting in the middle line of the palate, form a 
backward projecting angle. This curved border is smooth, non-articular, and it appa¬ 
rently forms the anterior boundary of the palato-nares. To the angle are attached the 
two vomers (v.), which are followed by the two pterygo-palatine bars separated by a 
median fissure. The palatine bone (pi.), a thin bar 6 millims. wide, is deeply grooved 
near its union with the pterygoid (pt.). This last bone has a remarkably stout 
central part or body, which is traversed obliquely from without and behind inwards 
and forwards by a prominent ridge, ending in an angular projection at the inner 
border. The position and the direction of this ridge approximately coincide with 
