OF THE SKULL IN THE UBODELOUS AMPHIBIA. 
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overlapped by, the face-plate of the maxillaries. Each bone is twice the size of the 
nasal. Bending inwards from its fore, broad, overlapped part, it helps to give an orbital 
margin to the skull in front, and then becomes attenuated where it ends in the middle 
of the superorbital region, just where the parietal runs under the frontal*. 
This very Varanian skull has no superorbital or lacrymal on the outside of the dense, 
large ecto-ethmoid. The frontals and parietals (f,p.) are nearly equal in size ; they are 
dense and smooth. The former dip a little towards the median suture, and the latter 
rise into a very gentle parietal crest. The frontals run under the nose-roofs nearly to 
the outer nostril ; behind they end at a transverse line over the optic foramina. 
The parietals (p.) form the coping of the skull-wall all along, reaching so far forwards 
as to underlie the ecto-ethmoidal tiles. A little deficiency appears between the ends of 
the frontals, precisely where, by more perfect ossification, the Lizard finishes its small 
pinhole-shaped “ parietal fontanelle.” 
The correlated growth of these now dense and finished parietals to the hind skull and 
ear-capsules has so completely modelled them over these parts, that it would seem as 
though they had been applied in a soft state, and then worked on to the subjacent 
structures. 
Although mainly roof-bones, their parietal portion is greater than in the Monitor ; as 
in that Lizard there is a supratemporal crest and fossa ; and in like manner the edge of 
the bone is notched gently to fit over the swelling on the prootic caused by the arch and 
ampulla of the anterior canal. 
The junction of the anterior and posterior canals (Plate 27. fig. 6) is just roofed over 
by the parietals at their posterior angle. They then run transversely across, with dentate 
edges, overlapping the front part of the occipital roof. 
If we would compare the parasphenoid of Ambly stoma (Plate 24. fig. 6, pa.s.) with 
that of Monitor, it should be for contrast. In the latter it is a most delicate style ; in 
the Urodele it is an almost complete floor for the large, fiat, barge-shaped skull. 
It is roundly notched in front, extended outwards towards the antorbital region, sub- 
carinate in the pituitary region, alate beneath the foramen ovale and Gasserian ganglion, 
and narrows rapidly towards its transverse hinder end. 
The vomers that did but form the back of the narrow arcuate rasp (Plate 24. fig. 5, v.) 
now (fig. 6, v.) are leaves of bone, as large as the leafy trabeculae of the Siredon. The 
row of teeth is arched in the opposite direction, namely, backwards, and occupies only 
the hind edge of the bone, where it overlaps the parasphenoid. 
Each vomer is now roundly notched at its outer margin for the internal nostril. 
The oblique outer margin in front fits by a jagged edge against the rudimentary 
palatal plate of the maxillary. 
These vomers are very Batrachian, but they are still larger than in the Frogs and 
Toads. The relation of the ragged outer edge to the narrow ingrowth of the maxillary 
* If the reader will compare this description and the figures with the skull of a Monitor and of a young bird, 
he will see how nearly this Amphibian skull approaches them. 
