610 
ME. W. K. PAEKEE ON THE STETTCTUEE AND 
near its end (Plate 55) ; but afterwards it also contracts an adhesion with the fore face 
of the auditory mass. 
It can be traced nearly up to the outer edge of the prootic (fig. 4, pro., pd .) ; and this 
coalesced “ pedicle,” before passing into the mass of the quadrate ( q .), gives off, from its 
posterior edge, a rounded condyle ( c.pd .); this is much smaller than in the Frog (see 
“ Frog’s Skull,” plate ix. figs. 2 & 7, i.h.m.)*. This coalesced bar and the condyle upon 
it are formed out of the primary apex or dorsal end of the mandibular visceral arch 
(Plate 55) ; but the “ pier” also attached itself to the otic mass, above , by the “otic 
process” (fig. 4, ot.p.). 
This process also coalesces with the auditory mass, namely, to the front of the tegmen 
tympani (figs. 3 & 4, t.ty., ot.p.) ; it is an upgrowth from the elbow of the pedicle 
(Plate 55) as the condyle is a downgrowth. 
From the point where these parts unite with the ear-mass there is a large fore-and-aft 
growth of cartilage ; that behind, which curves also downw r ards, is the quadrate (y.) ; 
that which runs forwards is the .pterygoid. The hinge of the quadrate nearly reaches 
backwards as far as the occiput, to give size to the gape, a state of things acquired 
during growth. 
The pterygoid {pg.) runs forwards, wide at first and narrow afterwards, from the pedicle, 
and its lower part is continuous with the inside of the posterior margin of the quadrate. 
Midway to the antorbital region the flat tape-like pterygoid stops ; then there is a tract 
of fibrous tissue, and these fibres fasten the pterygoid to the narrow postpalatine band 
( pt.pa .). As in Passerine birds, the palatine sends out an angular transpalatine 
process ( t.pa); it then runs forwards, retaining its larger breadth, curving a little 
inwards, and sending up the “ orbital process ” or ethmopalatine ( e.pa .) ; it then ends 
in a free prepalatine spike ( pr.pa .), whose flat upper end is attached by fibrous tissue 
to the palato-trabecular outgrowth. All this prequadrate growth is a development of 
the conjugational bar that ties together the anterior third of the 1st and 2nd bars in 
the skull of the embryo (Plate 55). In the Frog there is not any segmentation, either 
between the palato-trabecular bar (figs. 1, 2, e.pa.) or between the pterygoid and palatine 
(“ Frog’s Skull,” plate ix.). The free mandible of the Toad is quite like that of the Frog ; 
the “ inferior labials ” are not lost ; they ossify as mento-Meckelian bones which unite with 
the small dentary, and the ends of these are mutually united by an elastic ligament. The 
articular region and much of the rod is enclosed in an ununited ectosteal “ articulare”f. 
The next arch presents, perhaps, the most difficult problem in morphology ; I have in 
* I mistook this for part of the “ hyomandibular ; ” it is there called the “ infra-hyomandibular ” ( iJi.m .). In 
the adult Erog the pedicle cannot he traced further up than this condyle ; it, apparently, becomes fibrous above. 
I find that the bony plate which covers the inner face of this pedicle is much more distinct in the Bull-frog ; it is 
the “ metapterygoid,” and in the latter species there is a small “ mesopterygoid ” as well. In the Toad the 
pterygoid proper covers the diminished condyle. 
f Professor Htjxlet (art. “ Amphibia,” p. 75B, fig. 6, an.) calls this bone the “ angulare ; ” but it is united 
to the hardened rod itself in the “ Aglossa,” as in the Sauropsida. 
