LOWER LIAS. 
9 
The two halves of the mid-frontal have been separated along the medial line, 
and the right half depressed. The separation appears to have been at a suture, 
as is certainly the case with the nasal bones ; the medial margin of three fourths 
of the left frontal show the jagged, sutural character. I conclude, therefore, that 
the mid-frontal was divided, as in the Ichthyosaurus, and as in Varamis and 
Lacerta proper ; and that it was not a single bone, as in the Iguana and most 
Lacertilia, and as it is in the Crocodilia. Each half of the frontal in Scelidosaurus 
is a long, inequilateral triangle, the medial being the longest side, the posterior, 
which joins the parietal, the shortest ; the antero-external border is irregularly and 
deeply notched, uniting with the post-frontal, super-orbital, pre-frontal, and nasal 
bones ; it is excluded, as in Lacerta proper, by the large super-orbital bone ( 71 ) 
from the orbit. The outer surface of the frontal is sculptured by irregular lines 
and grooves, but less deeply than in Crocodilus. 
The post-frontal (12) forms the back and part of the upper border of the orbit, 
uniting with the super-orbital, the frontal, and malar, and sending backward 
an angular process to join the mastoid, completing the upper bar or zygomatic 
arch of the temporal fossa. This arch had been broken away on the left side 
(Tab. IV), but is preserved on the right side (Tab. V, 8 , 12). 
The pre-frontal presents a horizontal and a vertical portion; the former and 
larger part is wedged between the frontal, superorbital, and nasal bones, the 
descending plate joins the lacrymal (73), and touches the upper angle of the 
maxillary (21). In the Crocodile the aspect of the whole outer plate of the pre- 
frontal is upward ; in some Lacertians the major part looks outward. 
The nasal bones (15, Tabs. V and VI) unite above and behind with the 
frontal (11) by a short border, obliquely and irregularly cut, to include the pointed 
anterior ends of the lateral halves of the frontal ; the nasals expand as they 
advance, in union, first, with the pre-frontals, then with the maxillaries, where 
they slightly decrease in breadth. The mutilated fore part of the skull precludes 
the determination of the relations of the nasals with the pre-maxillary, and of the 
character of that bone. That of the outer plate of the nasals looks upward ; the 
maxillary border is slightly bent down (15, fig. 2 , Tab. V), and is overlapped by 
the maxillary (21, ib.) 
The fractured fore part of the skull in the above-cited figure shows the 
superior thickness of the median and lateral borders of the nasals, the intervening 
part being, as it w^ere, channeled below for the air-passage ; this has not here been 
divided by any ossified vertical septum ; the thickened palatal and alveolar parts 
of the maxillary, as they bend toward each other, present a convexity transversely 
to the nasal passage. This is closed below, as it seems, by the vomer (13). 
Of the hind part of the bony palate the pterygoid was brought into view by 
removing the matrix between the diverging rami of the mandible. The body of 
2 
