12 Mr. A. S. Woodward on the 



good preservation of" some of the hinder ])late3 reveals the 

 longitudinal median line of the head. The sutures between 

 the cranial elements are well marked ; and these are further 

 rendered conspicuous hy the predominant fusion of the super- 

 ficial tubercles into nodose rounded ridges directed at right 

 angles to the borders of the plates, as in certain species of 

 BotJivwIepis. 



Of the median occipital element only ])art of the anterior 

 margin remains (o). it is acuminate in front, the two halves 

 of the anterior border meeting in an obtuse angle mesially ; 

 but the lateral borders of the bone seem to have been parallel. 

 The posterior lateral plates (I) form a symmetrical pair, 

 meeting in a straight longitudinal suture for a short distance 

 mesially, and expanding outwards to occupy the whole of the 

 space between the antero-lateral Louiidaries of the median 

 occipital, the postero-lateral border of the second median 

 occipital, and the posterior border of th^ second pair of lateral 

 plates. Judging from the right side of the fossil, each of 

 these bones is broader behind than in front, but its precise 

 ])ostero-lateral extent cannot be determined. A fracture on 

 the left side reveals the impression of a downwardly (and in 

 part outwardly) descending plate from the external border ; 

 ■while an equally fortunate fracture on the right side in ad- 

 vance of the anterior end of the occipital plate exhibits another 

 vertical lamina of bone, almost transverse to the long axis of 

 the skull, but trending somewhat backwards within. These 

 two robust ossifications may perhaps represent the outer and 

 anterior elements of the otic capsules. The second median 

 plate of the cranial roof (oj is about as broad as the occipital 

 and seems to have been regularly diamond-shaped, though 

 its left antero-lateral portion is obscured. The second pair 

 of lateral plates is relatively small and represented only by 

 the element of the right side (2). This, however, is com- 

 pletely preserved. It is 2\ times as long as its maximum 

 breadth, and must have been separated from its fellow of the 

 opposite side by a considerable space, which was doubtless 

 occupied by other plates. The outer border of the bone is 

 nearly straight, but the inner border is much arcuated, with 

 a deep broad notch mesially. An adjoining but separate 

 fragment [z) seems to have originally occupied this notch ; 

 but the great overlapping piece of bone immediately on the 

 left must be considerably displaced, as proved by its size and 

 relatively coarse ornamentation. The outer longitudinal 

 border of the last-mentioned element is broken away, but it 

 is shown to be in direct continuity with a large thick lamina 

 of smooth unornamented boiie, which extends throughout its 



