238 
MR. W. K. PARKER ON THE STRUCTURE AND 
The foramen magnum (Plate 40, fig. 6, f.m.) is large and obliquely superior; the 
occipital condyles ( oc.c.) are large and posterior. Measured along the axis, the orbital 
region is longest, the nasal next, and the auditory the shortest; this part, however, 
is very wide, and the inner canals are very large and prominent; the posterior ( p.s.c.) 
has, over it, a spiny epiotic prominence (fig. 8, ep.). There is a narrow synchondrosis 
both above and below, dividing the continuous lateral bony tracts ( pr.o ., e.o.). 
The large, square parotic tracts are unossified at the tegminal edge ( t.ty .), and this 
is barely covered by the squamosal (sq.). There is a large cordiform, and two smaller, 
oval, fontanelles and the dividing tracts are unossified over the middle part, the bone 
retreating, laterally, in the prootic region. The lateral roof-edge of the endocranium is 
moderately wide, and the main fontanelle is nearly covered by the roof bones ( fp •)• 
The prootic encloses the preauditory nerves (III., V.) up to the moderate optic 
fenestra (II.) ; there the cartilage ( o.s.) is as extensive as the orbital part of the girdle- 
bone (etli.) ; that bone, however, runs far into the true nasal region, ossifying two-thirds 
of it; the broad overhanging snout is unossified in its front third. The girdle-bone runs 
well into its own wings, but it has not become anchylosed either with the palatines 
or vomers (fig. 7, pa., v.), as it does in the other species. The outer nostrils (e.n.) are 
very wide apart, the inner (i.n.) are scarcely more so, the whole fore face being so very 
broad. The outer angles of the largely ossified subnasal laminae (fig. 7) are but little 
more projecting than their general margin; the pro-rhinals ( p.rli .) are slender and 
uncinate. 
As in the other species, the etlnno-palatine cartilage is rounded oft in front, so that 
there is but little pre-palatine; the cartilage is much diminished in size, but it can be 
seen outside the palatines and pterygoids (fig. 7, ptpa., pa., pg.), where they meet, 
and it becomes large as it approaches the pedicle and quadrate (fig. 8). 
The two bony bars [pa., pg.) have the average Bufonine development, the first is 
falcate, and the second is arcuate and forked; it becomes very wide behind, but the 
part covering the pedicle, and ossifying it, is short. The part inside the quadrate 
reaches no further backwards, for the hinge for the jaw (q.c.) goes scarcely further 
back than the pedicle on the left side, but has retreated twice as far on the right; this 
arrest of the metamorphosis is a correlate of the unfinished form of the pre-palatine. 
The condyles (q.c.) are large, reniform, and oblique, the left is least transverse of the 
two. The height of the suspensorium (fig. 8) is great, although it forms but little 
more than a right angle, in front, with the axis of the skull. The part of the ptery¬ 
goid which passes inside the quadrate is pressed against the inner fork, and here there 
is a small crescentic aperture (blind), with its convexity inwards—a rudiment of the 
Eustachian passage (eu.). 
There is, as in P. varius, neither annulus nor columella; the stapes (figs. 7, 8, st.) is 
very large, oval, hollow, umbonate, and unossified. The stylo-hyal end of the hyoid 
(st.h.) is confluent, the whole bar (fig. 9, c.liy.) is narrow, and here is what I failed to 
find in the other two kinds, viz. : a projecting corner to the hypo-hyal. The notch 
