so MR. W. K. PARKER OX THE STRUCTURE AND 



with that of the whole suboccular bar (pterygo-palatine), whilst the point looks dii-ectly 

 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.jxi.) 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 foLu-th of the pterygo-palatine bar (Plate 12, figs. 2-4, pg.), is the thin 

 pterygoid foregrowth of the suspensorium, which was iu the antorbital region in the 

 last stage. 



The parasphenoid (Plate 12, fig. ^, pa.s.) retains its shape, but its point is more spUt, 

 and these two spikes end in a sulcus caused by the meeting of the ethmo-palatiues 

 {e.pa.) beneath the ethmoid : their commissure is elegantly bowed forwards. 



A thin ectosteal plate (Plate 12, fig. 3, jjg.) has applied itself to tlie "chondro- 

 pterygoid ;" this 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 23art in front retaining its thickness up to the meeting of the two regions. 



The suspensorium {e.pxt. 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 

 leached 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.%.), which did hang opposite 

 the ethmoid, is now tied by a ligament (hyo-suspensorial), so far backwards that its 

 styloid apex is du-ectly below the middle of the auditory capsule. 



This position is attained by the Axolotl when it measures 4i lines — that is, soon after 

 hatching (see " Urodeles," Part I., Plate 22, fig. 3, q., c.hi/.). 



In all this change of size, form, and relation, the enlarged " elbow " or otic process 

 (at. 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 11, fig. 7, pd.) tlie pedicle was becoming a mere thread 

 of cartilage, and the inner and posterior edge of the lateral bar was becoming solid and 

 rounded iu front of the groove where the facial nerve emerges. 



Now (Plate 12, fig. 3, ^jcZ.), 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 asfainst the convex fore face of the unossified wall of the vestibule. This 

 " condyle of the pedicle " is a process growmg from the under, as the otic process is an 

 outgrowth from the upper, part of the suspensorium. 



Over the outer surface, from wliich the orbitar process has vanished, a thin straggling 

 tract of membranous bone now lies ; this is the squamosal (wy.), with all the characters, 

 as yet, of a '' preoperculum." 



The little bridge of cartilage which arched over the facial nerve (Plate 11, fig. 8, 

 Vll.) is now once more free (Plate 12, figs. 2, 4, G, 7, ".(;/.) ; it is now an elegant 



