i 46 
MR. W. K. PARKER ON THE STRUCTURE AND 
The small, oval, directly posterior occipital condyles are separated by a concave 
space more than the width of both together, and more than half of this basal inter¬ 
condylar tract is cartilaginous. 
Also a wide “ cross ” of cartilage intervenes between the four main hind-skull ossifica¬ 
tions, below; above, the superoccipital synchondrosis is narrow, and the prootic and 
ex-occipital (fig. 1, pr.o., e.o .) of the same side are entirely confluent, the bony substance 
reaches to the squamosal (sq.) under which the “ tegminal edge ” is soft. Even below, the 
trigeminal nerve (fig. 2, Y.) passes through the bone, which is not far from the girdle- 
bone, over the optic nerve (II.). Some cartilage and three small membranous fontanelles 
lie across the hind skull, behind the large heart-shaped principal space. The breadth 
of the skull at the top lessens along the girdle-bone, in which, however, it spreads 
out again gently in front. This bone (eth.) takes up three-fifths of the orbital region, 
it passes, in front, nearly to the boundary of its own (ethmoidal) region, and above, 
runs a little along the septum nasi (s.n.). Over its wings this common ethmoid has 
a small superorbital “ eave ” of cartilage. 
The nasal region is very large both ways ; it ends abruptly in front, has large cres¬ 
centic roofs (fig. 1), a long and moderately deep septum (s.n.), and a wide floor (fig. 2), 
The pro-rhinals (fig. 2, p.rh.) are slender, but well formed and uncinate. The super- 
added cartilaginous valves of the external nostrils (u.V.u.P., e.n.) are large, and those 
passages are wide apart. 
Very wide apart indeed are the internal nostrils (i.n.) ; they are large oval holes con¬ 
verging forwards. The palato-suspensorial arch is large and well developed ; all its 
parts are wide, for width characterises the whole skull and all its parts. Yet, in 
essentials, both the cartilage and its grafted bones (pa., pg.), with the condyles of the 
quadrate and the pedicle (q.c., pel.), are quite normal. 
The Eustachian openings (eu.) are less than the inner nostrils, but are large; they are 
oval, with the long axis directed outwards and a little forwards. The annulus (a.ty.) 
is large, broad, and perfect; the stapes (fig. 4, .st.) is large, oval, and flattisli: it is 
broader in front than behind. The inter-stapedial (i.st.) is a thickish subquadrate 
segment, nearly half the size of the stapes; the medio-stapedial is long, straight, and 
its imperfectly ossified, wide, proximal end is scooped out; the extra-stapedial ( e.st .) is 
a reversed spatula—it is narrower distally than proximally, and has only a fibrous 
supra-stapedial band. 
The narrow stylo-hyal (fig. 2, st.h.) is confluent above; it increases only gently in size 
downwards (fig. 3, c.hy.), has no hypo-hyal lobe ( Ji.hy .), and soon reaches the basal plate 
as it turns backwards. That plate {b.li.hr.) is short, wide in front, narrow behind, has 
small fore-turned anterior, and long, slender, posterior lobes; the thyro-hyals ( t.hy .) are 
long and slender; they diverge so as to be at a right angle with each other. 
The mandibles (fig. 3) are quite normal, but are long and slender; the dentary (cl.) 
is half the length of the ramus. 
The investing bones are normal but partake of the general flatness and breadth of 
