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 Varanus 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 were, 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 



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