DEVELOPMENT OF THE SKULL IN THE BATKACHIA. 
643 
(Plate 59. figs. 3 & 8, q.), quite unlike what we see in the common kinds. Again I must 
refer to the separated pier (fig. 9), seen as attached still to the prootic (pro.), but having 
all the projecting parts of the bones cut away, so as to clear the view. As in the side 
views (figs. 3 & 8, q.), the elegant quadrate trochlea has its fore part tilted up, and, lying 
round and above this articular region, we see a squarish quadrate hone (q.), with the 
external process of the pterygoid bone (pg.) clamping its inner face (see also fig. 2, q.,pg.). 
But above the square quadrate there is another bony plate (less square in form) grafted 
upon the cartilage also: this is the quadrato-jugal ( q.j ., seen also in lateral view, fig. 8, 
q.j.). Over this is a third bone, only half as deep, and less strongly attached to the carti- 
lage; this is the squamosal ( sq . ; see also fig. 8 ,sq., where it is seen from the side). 
The last bone, the squamosal, invests the otic process ( ot.p .), whilst the pedicle (pd.) 
is the triangular tract of cartilage running from the outer to the inner side, where it is 
surmounted by the prootic (pro.) and supported by the pterygoid (pg.)*. 
The general relations of the squamosal and quadrato-jugal will be considered with 
those of the other investing bones. 
The ectosteal pterygoid (a huge bone) has eaten up all that cartilage which we saw 
in the last stage running from its broad root on the mandibular pier to the palatine 
region (Plate 58. figs. 2 & 3 ,pg., q.). This bone, below (fig. 2), is gently convex through- 
out ; its broad root is three-spurred : the inner and foremost of these spurs is a sharp, 
twisted style, which clamps the fore face of the prootic, external to the foramen ovale 
(pro., 5,pg.). The outer spur is like unto it, but grows outwards and backwards in an 
exactly opposite direction, clamping the inner face of the quadrate, as we have just seen 
(fig. 9). The inner spur is an elegant, large, auriform lobe ; it forms the outer solid 
floor of the tympano-Eustachian dome. Externally it lies under the ligamentous stylo- 
hyal (st.h.), hiding its attachment ; internally, it gives off a strong fascia, which is 
attached to half of the transverse ridge that runs across the parasphenoid, in front of 
the “ guard.” Thus we see that the pterygoid binds beneath the skull from the mid 
line to the quadrate, and the huge Eustachian passages meet behind the pterygoid fascia, 
to open as one in the roof of the pharynx. 
The stem of the pterygoid is first broad and then narrow. At first it elbows out 
towards the cheek, just catching the long squamosal spur ; it then runs forwards and a 
little inwards, and is spliced on to the inner face of the postpalatine cartilage (pt.pa .). 
The pterygoid is distinct from the palatine — not, however, as in the Toad (Plate 54. 
* The Batrachia are constantly breaking down in the matter of parostosis and ectostosis, which are true enough 
as distinctions in the higher groups. In the outer views of the quadrato-jugal I have left the bone (q.j.) 
uncoloured ; but the part grafted upon the ascending otic process of the quadrate (fig. 9) is coloured, because 
here it acts the part of an “ ectosteal ” plate. I now have the satisfaction to agree with Professor Huxley 
(art. “ Amphibia,” fig. 9, Qu.J., p. 755) as to the proper homology of the styloid hone which is attached by its 
broad, hinder end to the quadrate in the Frog and Toad (Plate 54. fig. 7, q.j.). Its ectosteal relation to the 
quadrate cartilage in the common kinds was a stumbling-hlock to me, and in my former paper it is called the 
quadrate (“ Frog’s Skull,” plate ix. q. & qu.). It is one of the common instances in this group of one bone taking 
the functional place of two. 
4 U 2 
