DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
141 
and angles of subnasal laminae (p.rh., s.n.l.) —are not ossified. The pro-rhinals are 
triangular, pointed and in-turned, as in the genus Bufo; inside them the passages 
( n.n .) for the terminal branches of the “ orbito-nasal ” nerves are large. 
The thick roof hides the fontanelle, but I suspect it to be single, as in the thin skull 
of Bombinator (fig. 1). 
That I should claim for the pterygoid and palatine bones (jpg., pa.) the title of enclo- 
skeletal and “ectosteal” will not seem very strange if the condition of these bones in 
Pelobates is considered. All, or nearly all, the cartilaginous palato-suspensorial arch 
has been eaten by these strong bones. Here the palatine (fig. 6, pa.) has the form of 
a hatchet blade, for it has taken up the prenasal spike ; it is deeply notched, and 
half the long-oval, transverse inner nostril ( i.ri .) is in this notch, and the hole is finished 
inside by the vomer and wing of the ethmoid (v ., eth.). Curving elegantly round in the 
hollow of the maxillary (mx.) the palatine meets the pterygoid ( pg .); seen from below, 
these two bones appear of equal length : a thing contrary to rule. 
The pterygoid (fig. 6) has the strength of a “flying buttress,” jammed in between 
the clentary and palatine laminae of the maxillary (mx.), and then springing obliquely 
across to clamp the front of the hind skull over the reduced and useless “ pedicle,” it 
fixes and binds the cheek to the cranium. That inner fork, like a strong foot, stands 
stoutly on the prootic, and is sutured to the parasphenoid (fig. 6, pr.o., pa.s.). The 
outer fork passes back outside the minute Eustachian pouch (eu.), and clamps the 
inside of the quadrate (cp), the distal part of this huge “pier.” By grafting of the 
quadrato-jugal (q.j.) on the cartilage, this part also is well ossified, all but the large 
convexo-concave reniform condyle ( q.c .). 
Answering to its pier, the mandibular arch (fig. 10) is unusually stout; yet it does 
keep the Meckelian rod—its pith—unossified. The mento-Meckelian ( m.mJc.) is well 
developed ; the dentary ( d .) is continued from it as a strong splint along the front 
two-thirds of the arch; and the “ articulare ” (ar.) forms a strong inwardly crested 
trough for the primary cartilaginous rod. 
I can find no “ annulus tympanicus;” the spiracular cartilage is probably combined 
with the edge of the “ tegmen.” The stapes (figs. 8 and 11, st.) is rather large and 
has an “ umbo ;” its form is three-fourths of a circle, with the hind margin cut away 
to fit against the sub-convex bony margin of the fenestra ovalis, behind. The columella 
(co.) is a little phalangiform bone, as long as half across the stapes, thick behind, thin 
in the middle, and knobbed at its free end; it fits against the inferior margin of the 
stapes, just below the facial nerve (VII.). The stylo-hyal (st.h.) has a pedate end which 
articulates with the auditory mass close behind the minute Eustachian pouch (eu.). 
The continuation of the hyoid bar gently increases in size until it conies to the hypo- 
hyal region (fig. 9, c.hy., h.hy.) ; that part is a large rounded ear of cartilage, which, 
behind, passes by a broad stem into the basal plate (b.li.br.). The cerato-hyal has two 
small osseous centres in it; a rare modification. 
As in the Hylidse, the pre-basal notch is of great depth, and the basal plate of small 
