226 
MR. W. K. PARKER OK THE STRUCTURE AND 
( p.n.) is more definite than in that type. The occipital ring projects less ; the condyles 
are separated by their own width only, and they are large and not posterior, hut 
postero-inferior. The synchondroses above and below (s.o., b.o.) are equal in both, 
and have an endosteal deposit. The roof is less wide behind, shows only the large 
fontanelle, and the tegminal growth is altogether less, so that the fontanelle takes 
up more than three-fourths of the roof. The sides of the occipital ring and the 
auditory capsules, with their convex canals, are all continuous in their bony invest¬ 
ment, right and left ( e.o ., to V.) ; and there is the same small headland unossified 
at the very limited tegminal edge ( t.ty .). There is cartilage also where the pedicle 
fits on, and where the stylo-hyal unites beneath, with the skull (pel., st.h.) ; also in 
front, below, the large optic fenestra (II.) is surrounded by cartilage, and the foramen 
ovale (Y.) by bone. 
The gradually narrowing orbital region is more overlapped by the roof-bones (fig. 9, 
f.p), and three-fifths of the wall is unossified, and nearly all the floor. The lateral 
rudiments of the girdle-bone (eth.) are less, and run into their own alse partially; yet 
an endosteal deposit, with scarcely any perichondrial bone (ectosteal palatine), runs 
up to the cheek. These ethmoidal wall-bones reach the roof externally (fig. 8), but are 
separated by their own width below (fig. 9). Here we have a much more perfect 
median bone than in Pseudophryne (Plate 42, fig. 2), for the intertrabecular bar 
is ossified for the fore half of its extent. In front, the base of the septum nasi (s.n.) 
is ossified almost up to the rostrum (p.n.), and between the lateral ethmoidal centres 
(etli) the bony deposit is continued for some distance in two tracts ( p.e.). Here we 
have the continuous “ mesethmoid ” of the Ostrich Family foreshadowed, in which the 
bony deposit also takes place right and left of the cartilaginous wall. 
The unossified roof and floor (below n., and above s.n.l.) are moderately wide ; the pro- 
rhinals (fig. 9,p.rh.) are small and sharp ; the prenasal (p.n.) is rather large, the front is 
sinuously transverse and of medium width, and the sub-tubular nostrils are defended 
by well-developed valves (u.P-.u.l 2 ). The ethmo-palatine (e.pci.) is slender, and the 
external part adze-shaped ; the bone (fig. 9, a) is mainly endosteal, and the post-palatine 
tract is either separated from the pterygoid cartilage, or united by a very fine thread. 
The pterygoid (pg.) is typical, and partly ossifies a free pedicle (pd). The quadrate 
is unossified ; the condyles (q.c.) reniform and oblique; and the Eustachian openings 
(eu.) are only half the average size. The same may be said of the annulus (a.ty), 
whose horns are not united. 
The stapes (figs. 9 and 10, st.) is not so large as in Pseudophryne , and only 
half as convex; its margin is cartilaginous, the rest is thin bone; its oval form is 
modified by a slight emargination before and behind. The columella (fig. 10) is almost 
of the average size; the whole rod is continuous; there is a semi-osseous enlarge¬ 
ment of the medio-stapedial (m.st., i.st.) behind, but no joint, and the bone is arched 
and geniculate; the extra-stapedial (e.st.) is a small oval shield, with a free supra - 
stapedial spike. 
