DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
77 
indeed now, it will soon become less than one-fourth its present size. Even now it 
is less than a fourth the size of that of the young Tadpole (A, Plate 2). 
Relatively to the cranium, it is immense, yet, and retains all the larval characters, 
being still confluent with the chondrocranium at three places, 
The pedicle (pd.) is now a very narrow band, and like the pterygo-palatine, is at 
light angles with the main bar. 
The “elbow” of the suspensorium has developed a new “otic process” ( ot.p .), and 
the spiracular band has become a mere thread (Plate 11, figs. 6, 7, sp.c.). 
As in the “Urodeles,” the permanent “otic process” (ot.p.) mounts up against the 
fore edge of the tegmen tympani and the swellings caused by the ampullae : it reaches 
inwards, as in them, to the anterior ampulla, and even a little further. 
Above (fig. 6), it is a thick, rounded mass, but below (fig. 7), it is flat; it has, as it 
were, been thrust back against the auditory mass, and cleaves to, and lies outside, 
as well as in front of it. 
The greatly developed ridge on the edge of the suspensorium, instead of passing in 
a gentle arc forwards to become the thickened edge of the orbitar process, turns 
suddenly as a round loop, and then, at an acute angle, bends back again round the 
front margin of the orbitar process, scarcely dying out as it approaches the condyle of 
the quadrate, in the front of the face; all this growth is ready to vanish away. 
This swollen upper selvedge is thickest behind, then narrows up to the apex of the 
orbitar process, and keeps its breadth until it dies out in front. 
The quadrate region and condyle (Plate 11, figs. 6, 7 ; and Plate 12 fig. 1, q.) is 
very broad and also thick, especially at its outer edge. 
In conformity with the divergence of the quadrate bars the mandibles (Plate 12, 
fig. 1, rah) are considerably longer; but the lower labials (LI.) are full sized, as yet, 
and the condyle for the hyoid (hy.f.) is perfect. 
So also is the bar itself (c.hy.), but one can see that the styloid region (st.h.) is 
elongating. 
In the Common Prog and Toad there is no upper hyoid element until about three 
months after the loss of the tail; in Pseudis the tail has lost only two-sevenths in 
length, although much narrower, when that element (the epi-hyal or “columella”) 
appears. Here, at any rate, this rod appears much earlier, relatively, than in the 
common kinds; it is possible, however, that the Tadpole, at this stage, may be several 
years old. 
In these large Tadpoles it is as easy to show that the early “ stapes ” belongs to the 
periotic capsule as that this late segment does not. There are two cartilages, besides 
the stapes, in certain “ Proteidea” (e.g., in the Menopome), both inside the facial nerve. 
The upper piece sends its narrow proximal part to the stapes ; the lower cartilage, 
manifestly part of the epi-hyal, becomes partly confluent with the hind margin of the 
suspensorium. 
Here things take a very different course, for the cartilage (Plate 11, figs. 8, 9) is 
undivided, and forms a rudimentary epi-hyal. 
