72 
MR. W. R. PARKER ON THE STRUCTURE AND 
The nasal capsules are membranous as yet; and this crescentic ethmoidal wall, 
which articulates with the “ tegmen,” bounds them behind. 
The dorsal element of the mandible, or its “suspensorium,” is the most extraordinary 
thing in this remarkable “chondrocranium.” Each bar is equal in size to the combined 
trabeculae cranii, and to each is suspended three other cartilages, and a ‘process which 
becomes a free ray ( ot.p .). 
The dorsal end of this bar early coalesced with, or rather grew from, the trabecula, 
beneath the emerging trigeminal nerve (V.); that part is now narrow, but terete; an 
elegant crescentic margin to the subocular fenestra (Plate 2, figs. 1, 2, s.o.f. ) is formed by 
this “ pedicle” as it passes outwards and forwards, and becomes the main bar ; that bar 
is becoming rapidly widened, so as to be live or six times the breadth of the dorsal end. 
A rounded notch exists between the “pedicle” and the spiracular cartilage ( ot.p .), 
and this cartilage is continuous with the tegmen tympani at its distal end, and with 
the “ elbow'’ of the suspensorium at the proximal end. 
The “elbow” of the suspensorium passes outwards into the cheek as a large 
projection, with a rounded outline; the bar is then bent in a falcate manner, so as to 
run into the face where the ethmo-palatine projects. In front of this, opposite the 
middle of the large conjugational tract, there is the pyriform, gently concave condyle 
for the cerato-hyal; it is just beneath the edge of the bar (Plate 2, figs. 1 and 2, hyf.). 
Over this part the larval Batrachian “ orbitar process” grows upwards and inwards 
as a sessile, semi-oval leaf, with decurved edges and a swollen base ; it is attached 
to the post-palatine crest by a short ligament, and is not confluent as in Bufo 
vulgaris. 
The decurrent enlargement of its edge runs backwards insensibly into the main bar 
as a thickened margin; in front, it projects over the edge of the bar as a free point, 
and then runs along the rest of the bar as a selvedge (Plate 2, fig. 1, or.p.). 
From thence the anterior fourth of the suspensorium is a many-sided flap, not sensibly 
lessened in width, and having on the outside a snag, and in front the convex sinuous 
condyle of the mandible ( q .), which looks a little inwards, and is only a trifling 
distance behind the cornu trabeculse. 
That ending, however, is but the beginning of the proper mandible, which is a stout, 
transversely-directed, sigmoid bar (Plate 10, fig. 5, mk.) ; it is twisted and notched 
(like the human ulna ) to roll upon the quadrate. To its flattened inner (distal) end 
is attached the lower labial (Plate 10, fig. 5, l.l.), a thick, short, arcuate bar, lessening 
in size downwards, where it is attached by a strong ligament to its fellow to form the 
horseshoe, or imperfect suctorial disk. The elongated angle of the upper labial (u.l.) 
overlaps the double jaw-piece (labio-mandibular), and is represented by a separate 
cartilage in the Lamprey, and in the Tadpoles of many kinds of Batrachia. 
The hyoid (Plate 10, figs. 5 and 6, c.hy.) is a large irregular lozenge of cartilage, 
growing towards the mid-line below, and connected to its fellow by simple cartilage 
{c.hy., b.hy.). Externally, or above (Plate 10, figs. 5 and 6, c.hy., st.h.), it sends out a 
