DEVELOPMENT OE THE SKULL IN THE BATRACHIA. 
243 
B. b. Toads with digital disks. 
First Family. “ Hyl/EDACTYLId^.” 
Ear perfect; toes webbed ; sacral apophyses dilated ; and no parotoids. 
Genus Callula. 
72. Callula pulchra. —Adult female ; 2f inches long. Pegu. 
This is one of the shortest of the Batrachian skulls; the longest of which are short 
compared with those of other groups. The length, including the projecting occipital 
condyles, is scarcely more than three-fourths the breadth, but measured along the base, 
less than three-fourths (Plate 44, figs. 8, 9). The condyles of the quadrate end a little 
behind the fore edge of the parasphenoidal wings. If the outline of the face and 
cheeks were produced into a whole ellipse, the short diameter of that ellipse would 
bear, to the long, the proportion of 9 to 10. 
The retreat of the hinge of the jaw is about equal to that of an average skull in 
the “Urodeles,” and to what is seen in the type form at the time of transformation. 
So far as to form; as to texture and substance, this skull is like that of any ordinary 
“ Caducibranch ” among the tailed Amphibia ; and quite unlike the normal Anurous 
type of skull, for the bony tracts run past all the normal landmarks. 
As to proportion of the parts, in detail, I may instance the usually small size of 
the “ epi-hyal ” element—transformed into the columella—which makes it seem, in 
most kinds, so poor a representative of the hyomandibular of Fishes; that is not a 
difficulty here (Plate 44, fig. 10, m.st. e.st.), for with its new form and functions it 
keeps its old size and proportions. The skull is well roofed, but much in the manner 
of the Oriental Anura, generally; the outer bony tracts are moderately thick, and 
keep their sutures well. 
The occipital condyles ( oc.c .) are large, bold, oval, and postero-inferior in position; 
they are separated by a gently emarginate tract two-thirds their own width. 
The foramen magnum (fig. 8) is oblique, and looks upwards; the floor, behind, is 
quite ossified (fig. 9, b.o.); the roof has an exposed pentagonal tract of cartilage 
(fig. 8, s.o. ), one side of which borders the foramen magnum ; the passage for the 9th 
and 10th nerves is not divided. The auditory capsules show their canals strongly 
outside (fig. 8, a.s.c., p.s.c., li.s.c.), but the upper face is very much narrower than the 
lower, so that the stapedial series is well seen from above (fig. 8, m.st.), and when these 
are removed, the floor of the tympanum and the fenestra ovalis are seen. Beyond 
the horizontal canal the prootic region of bone projects like a handle, and this narrow 
prootic tract ends in a short and narrow unossified tegrnen tympani ( t.ty .), which is 
hooked in front, and from this hook, inwards, the face of the capsule is obliquely 
bevelled. Below (fig. 9), there is one continuous occipito-otic tract of bone from side 
to side, cartilage only remaining {of basal origin) to form a subconcave facet for the 
pedicle {pdf and just where, behind this part, the stylo-hyal {st.h.) is confluent. 
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