DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
1G5 
ovalia (V.) on their upper edge, reaching from thence to the pedicles {pel.). Beyond 
the horizontal canal the capsule lessens to one-third its breadth, to form the “tegmen” 
(fig. 1). The fore and hind skulls are equal in length ; the mid skull is one-half longer, 
and relatively broad ; its sides are sinuous, for it dilates a little both in the temporal 
and ethmoidal regions. The actual floor of the chondrocranium is only half the width 
of the roof, and the optic nerves (II.) pass out of the end of a long, oval fenestra, which 
reaches to within a short distance of the ethmoidal wings. Measured from the hinder 
margin of the actual optic foramen to its fore end, this fenestra takes up four-fifths of 
the orbital wall, and the girdle-bone {eth.) does not even reach to the fore edge of the 
fenestra. A narrow band of cartilage bounds the single, great fontanelle (fo.), and as 
this widens in front it becomes bony ; the fore margin of the fontanelle is bony, but the 
tegmen cranii thus ossified is a very narrow selvedge, and this band only reaches to 
the very definitely marked nasal roofs, whilst the bone runs very slightly into the 
septum {s.n.). Laterally, there projects a narrow superorbital eave beyond the bone, 
and the ossification projects slightly into the wings. 
The nasal septum [s.n.) is thick behind and bulbous in front; its junction with the 
roof-cartilages is shown in front, where the short decurved “ rostrum” ( p.n.) has a small 
projection on each side of it, the right being the largest ; these are the ends of the 
crescentic roof-tracts, which are large and wide. 
Below (fig. 2) the floor is very wide, and ends in front in the primary angles of the 
cornua trabeculae, and in the smaller, secondary, decurved pro-rhinals {s.n., p.rh.). 
The narial openings are wide apart, the external nostrils {e.n.) being three-fourths 
the distance from each other of the inner holes {i.n .); the outer openings are protected 
by the normal valves {u.V-.u.V 1 .). The palato-suspensorials are slender, but quite 
normal; from the ethmoidal wing, which thickens round the hinder margin of the 
inner nostril, the ethmo-palatine becomes a moderate tape of cartilage, expanding 
into the spiked pre-palatine band, which runs backwards as a post-palatine, with a 
rounded hinder lobe projecting into the maxillary, and then becoming pterygoid 
{pr.pa., pg.). The forks of the suspensorium are apparently nearly equal, as seen 
from above and below, but the quadrate region and its condyle (q.,q.c.) pass further 
backwards, reaching as well some distance downwards and outwards. The palatine 
bone {pa.) is the normal falcate thin piece, and the pterygoid {pg.) has the usual 
shape, but, contrary to rule, it covers the cartilage most above and least below. 
The bulbous pedicle is most seen above ; below, it is confluent with the stylo-hyal (pd., 
st.h .)—a rare modification , and seen again in Phyllomedusa hicolor (Plate 34, fig. 8). 
Above, in front of the fork, the pterygoid-bone is rough and hollowed out; it is thin and 
lathy where it binds on the inner face of the quadrate. That region is only slightly 
ossified by the quadrato-jugal {q.j .); its condyle {q.c.) is large, elegantly bilobate, with 
the inner or hinder lobe much the larger of the two. 
The annulus {a.ty.) is rather small and open above; the stapes (fig. 5, st.) is oval, 
with an emargination antero-superiorly, and an external boss. The pistol-shaped 
