562 
ME. W. K. PAEKEE ON THE STEUOTUEE AND DEVELOPMENT 
of the last, and, metamorphosing late, probably would never have gone beyond the 
cryptobranch condition. 
On the whole, the description just given will serve for this; but there are several 
points of difference that must be noticed. 
The bony deposits and plates are denser, and there is altogether a nearer approach to 
the Salamandrian type of skull. The hyo-branchial cartilages are as large as in the last, 
but the second basibranchial has acquired a bony centre (Plate 27. figs. 1 & 5). 
The exoccipitals, prootics, pterotics, and spheno-ethmoids (Plate 24. fig. 5, and 
Plate 27. figs. 1 & 2, eo.,pro ., pto , sp.e.) are unaltered. The stapes is now a very solid 
cone of bone, and its fan-shaped ligament is seen to pass above the portio dura to be 
inserted into the edge of the suspensorium (Plate 24. fig. 5, and Plate 27. fig. 1, st. 7). 
Thus we have here what may may be called a spiracular fascia, the counterpart of the 
spiracular cartilage and bone of the Menopome and others. 
There is still a large tract of cartilage in the cranial wall, through the fore part of 
which the optic nerve (2) passes. The bony tract (sp.e.) only reaches to the front margin 
of the great basal fontanelle, which is margined by a huge tract of internasal cartilage 
( i.n.c .), the outer angles of which have the olfactory crura lying across them. 
A great change has taken place in the antorbital cartilage (Plate 27. fig. 3, e.pa.). 
Instead of being a tongue-like flap, projecting outwards and looking forwards, it is now 
a flat, oval wedge, with its narrow end in front, and closely applied to the articular face 
of the projection of the ethmoid to which it belongs. 
This is a rare condition in the Urodela, for this cartilage generally retains its relative 
size and coalesces with the back of the nasal roof. In the next stage we shall find the 
palatine bone assuming a rare condition also, being directed transversely outward, instead 
of gaining a longitudinal position (Plate 24. fig. 6, pa.). 
But at present the palatine bones (Plate 24. fig. 5, pa.) are more nearly parallel with 
the axis of the skull than they were. One thing is noteworthy, namely, that there is a 
definite space between them and the pterygoid bones. 
The vomers, premaxillaries, maxillaries, and squamosals all retain their larval condi- 
tion (Plate 24. fig. 5, and Plate 27. figs. 1 & 2, v.,px., mx., sq.); but the parasphenoid 
( pa.s .) has become more elegant in form, and is nearer to the state it assumes in the 
Salamandrian stage (Plate 24. figs. 5 & 6) ; its ethmoidal region is more outspread, and 
the basitemporal angles are more definite. 
Professor Huxley has always contended with the writer for a continuity of both the 
pedicle and ascending process with the base and side wall of the skull in the Axolotl. 
This I could never see in the pedicle. I have shown that the ascending process is con- 
fluent with the cartilaginous skull-wall ; but the pedicle is very short for some time, 
and never coalesces with the skull. Its relation is to the antero-inferior part of the 
auditory mass, where that is plastered over with secondary cartilage. 
A section through the top of the suspensorium at this stage (Plate 27. fig. 4) shows 
that the pedicle is quite distinct from the auditory capsule (pro., a.s.c.). The section 
