80 
MR. W. K. PARKER ON THE STRUCTURE AND 
with that of the whole snboccular bar (pterygo-palatine), whilst the point looks directly 
forwards. 
It forms now a pointed wing to the fore third of the crescentic palatine region ; the 
upper process of which {e.pa.) is half the length of the post-palatine ( pt.pa.) which ends 
opposite the middle of the optic fenestra (II., o.s.f), whereas in the last stage it ended 
opposite the middle of the internal nostril (Plate 11. fig. 6). 
The last fourth of the pterygo-palatine bar (Plate 12, figs. 2-4, pg.), is the thin 
pterygoid foregrowth of the suspensorium, which was in the antorbital region in the 
last stage. 
The parasphenoid (Plate 12, fig. 3, pct.s.) retains its shape, but its point is more split, 
and these two spikes end in a sulcus caused by the meeting of the ethmo-palatines 
{e.pa.) beneath the ethmoid : their commissure is elegantly bowed forwards. 
A thin ectosteal plate (Plate 12, fig. 3, pg.) has applied itself to the “chondro- 
pterygoidthis latter part, although it is not segmented off from the post-palatine as in 
the genus Bufo, is yet quite distinct from it to the eye, it being suddenly compressed; 
the part in front retaining its thickness up to the meeting of the two regions. 
The suspensorium (e.pa. to q.c.) has shrunk to one-fourth the size it had in the last 
stage; it has lost the large leafy orbitar process; and the quadrate condyle which 
reached to the frontal wall of the head, now reaches nearly as far back as the “fenestra 
ovalis.” 
The hinge for the hyoid has also gone, and that bar ( c.hy .), which did hang opposite 
the ethmoid, is now tied by a ligament (hyo-suspensorial), so far backwards that its 
styloid apex is directly below the middle of the auditory capsule. 
This position is attained by the Axolotl when it measures 4^ lines—that is, soon after 
hatching (see “ Urodeles,” Part I., Plate 22, fig. 3, q., c.hy.). 
In all this change of size, form, and relation, the enlarged “ elbow ” or otic process 
( ot.p.) has been the fixed point, and the quadrate has been thrust back by the reversed 
curve and increased length of the ethmo-palatine. 
In the last stage (Plate It, fig. 7, pel.) the pedicle was becoming a mere thread 
of cartilage, and the inner and posterior edge of the lateral bar was becoming solid and 
rounded in front of the groove where the facial nerve emerges. 
Now (Plate 12, fig. 3 , pdf), the attenuated pedicle has become fibrous proximally, 
and the outer part has developed itself into a thick pedate mass, the concave side 
of which fits against the convex fore face of the unossified wall of the vestibule. This 
“ condyle of the pedicle ” is a process growing from the under, as the otic process is an 
outgrowth from the upper, part of the suspensorium. 
Over the outer surface, from which the orbitar process has vanished, a thin straggling 
tract of membranous bone now lies; this is the squamosal (sq.), with all the characters, 
as yet, of a “ preoperculum.” 
The little bridge of cartilage which arched over the facial nerve (Plate 11, fig. 8, 
VII.) is now once more free (Plate 12, figs. 2, 4, 6, 7, a.ty.) ; it is now an elegant 
