76 MR. W. K. PARKER ON THE STRUCTURE AND 
The ethmoidal wall behind the nasal sac was articulated to the “ tegmen cranii" 
(Plate 2, fig. l) ; that joint was lost in the last (Plate 11, fig. l) ; now a new 
articulation has appeared, namely, of the post-palatine crest with the ethmoidal wall 
(Plate 11, fig. 6, pt.pa.) ; this, however, is merely at its upper part; the bar is 
continuous with the skull below (Plate 11, fig. 7, ppgT). 
The direction of the endoskeletal palatine (“ post-palatine ”) was directly forwards 
(A); the pre-palatine point being slightly turned inwards to join the trabecula by a 
ligament (Plate 2, fig. 1 , pt.pa., prpa.). 
Afterwards (B, Plate 11, figs. 1-3), the pre-palatine point was well developed, and 
turned directly inwards to join the trabecula, but the main piece was parallel with the 
skull; the sharp crest had become an even thick ridge. 
Now (C, Plate 11, fig. 6 ; and Plate 12, fig. 1, pt.pci.), this part has behaved like a 
railway signal : it lias turned outwards, almost directly, but is bent a little forwards; 
the pre-palatine has again become reduced to a mere point carrying the ligament that 
runs to the cornu trabeculae. 
The flat, but crested, bar (A, Plabe 2, fig. 1 , pt.pa.) has become a massive, rounded 
rib of cartilage, standing high above the thin pterygoid plate that unites it with the 
suspensorium (Plate 11, fig. 6, ppg.) ; thus that outer bar now stands olf a good 
distance from the skull, 
The tegmen cranii has grown well over the perpendicular ethmoid, and the septum 
nasi has become surmounted by a pair of thick crescentic folds, lying back to back 
(Plate 11, fig. 6 ; and Plate 12, fig. 1, cd.sp.) ; from these the cartilage grows to some 
little distance over the nasal sacs, but I cannot find, either now or afterwards, any 
such clearly distinct nasal roof as is seen in the species of Rana. 
The anterior part of the skull has become reduced in size and modified to a much 
greater extent that the outer bars; thus the quadrate hinges (q.) are now a sensible 
distance in front of the cornua trabeculae. 
These latter parts are now very small and bifurcated; the inner lobe is a short hook, 
( c.tr.) pointed inwards; this will be the pro-rhinal, it lies in front of the nasal sac ; the 
outer lobe is a long “ear” of cartilage ( s.n.l .) directed outwards and little forwards, 
and attached by ligament to the prae-palatine spur ( pr.pa.). 
The position of the pre-palatine ligament shows the amount of lessening the 
trabecular cornua have undergone, for the ligament and this outer cornu, together, 
form the fore boundary of the internal nostril (i.n.). The last stage (Plate 11, 
figs. 1, 2, c.tr.) shows how much of the cornu there was then in front of that passage. 
The ethmo-palatines meet below (fig. 11, ppg.)) there was no such appearance in 
the last stage, before these bars had turned round (fig. 2); here, if the segmental nick 
(fig. 6), which is seen above, had extended between the post-palatine and the trabecula, 
it would have severed it from the skull, beneath which the right and left bars are 
confluent. The sub-cranial confluence is peculiarly Petromyzine. 
The huge suspensorium (sp., q.) is being folded up that it may be changed; huge 
