204 PROF. W. K. PARKER ON THE STRUCTURE AND 
As a Urodele, we shall see in the next stage (Pl. XLI.) that this species becomes a 
culminating type; as a Vertebrate it, in a sense, stands still, and even recedes; we 
must find another “sucker” before we shall see the blossoming of any thing more 
perfect than the Menopome and the great Salamander show. 
The Skull of the adult Triton cristatus. 
A. Investing Bones. 
The main part of the Newt’s skull is nearly oblong, the sides only converging gently 
from behind forwards; a line drawn completely round it would be a very regular 
ovoid, the fore half a semiellipse, the hind half a semicircle. 
The parietals and frontals (Pl. XLI. fig. 1, p,f) are large, dense, and permanently 
distinct ; and the teeth of the sutures are few and very large. The sinuous hind margin of 
the dilated temporal part of the parietals does not hide the supraoccipital synchondrosis, 
nor cover the posterior canals (p.s.¢). Each temporal wing has its sinuous outer 
margin parallel with the axis, and separated from the orbital part by a gently concave 
space. 
There are four or five large sutural teeth on each side, strongly interlocked ; and the 
fore margin of the parietals is hidden by the large “teeth”? of the sguamous coronal 
suture. 
The frontals (f) have only two definite teeth, right and left, along the frontal 
suture ; these bones are gently convex, oblong, and, in turn, covered by the “teeth” of 
the overlapping nasals. 
The parietals and frontals (fig. 3, p, f) have a moderate orbital downgrowth, equal to 
the sphenethmoidal wall (sp.e). The nasals (z) are oblong, and are separated by the 
grooved nasal process of the premaxillary (7. px); their upper surface is convex and 
rugous, their edges dentate; the fore margin is obliquely notched, to make space 
antero-laterally for the nasal roof and apertures (na, e. 7). 
The squamosal (sq) is a strong wedge of bone; it articulates above and behind with 
the posterior angle of the parietal, bites into the top of the auditory capsule, has a 
transverse subapical ridge, which sends down from its middle a short crest and a nail- 
like preopercular process, which, in turn, binds down on the suspensorium as it runs 
downwards, outwards, and forwards; it overlies the edge of the suspensorium. 
Outside the junction of the nasals and frontals there is a supero-lateral bone, the 
outer ethmoidal or prefrontal (p,f); it is subtriangular and convex, and is wedged in 
between the upper bones and the maxillary beneath (fig. 3, pf); the prefrontal is 
perforated and grooved for the nerves and vessels of the fore face. The whole margin 
of the premaxillary (px) is now only three fifths as long as that of each maxillary 
(mx); its palatal face has a considerable breadth behind the marginal belt; its sides 
are sutured to the maxillaries, and its concave hind margin to the vomers (fig. 2, v). 
