DEVELOPMENT OF THE SKULL IN THE BATRACHIA 
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1. The extremely flat form of the skull, generally. 
2. The intense ossification of the occipito-otic and ethmoidal regions. • 
3. There is but one, that a very large, fontanelle. 
4. The prenasal is present, and the lesser cornua (pro-rliinals) are half the size of 
the outer angles of the snout. 
5. The superorbital tract is distinct as a semi-oval eave. 
6. The nasal roof is very narrow, as compared with the floor. 
7. The annulus has its horns wide apart. 
8. The pedicle is very solid, and the Eustachian opening is margined behind by a 
confluent stylo-byal. 
9. There is neither a separate inter-stapedial nor a supra-stapedial band. 
10. There are no lobes on the hypo-hyals, and no antero-lateral lobe on the very 
small basal plate. 
11. The roof-bones are extremely arrested and narrow. 
12. There are no septo-maxiflaries. 
46. Hyla phyllochroa. —Adult female ; 1 inch 5 lines long. Cape York, Australia. 
This skull resembles the last very much, but is altogether frailer, and less ossified ; 
I am not aware of having dissected a skull more light and delicate than this; its main 
rivals are some of those of its own country, viz. : Rappia bicolor, and Camariolius 
tcismaniensis. 
The outline of this skull (Plate 31, figs. 6-9) is elegantly semi-oval; it is much 
shorter than the last, the breadth being to the length as 7 to 6, and the condyles of 
the quadrate have retreated much further back, being opposite the proximal part of 
the occipital condyles. These condyles project as little as in the last, are smaller, and 
differ in direction, being exactly posterior. 
Both skulls are equally depressed, but this differs in shape in all the three regions. 
The auditory capsules are only three-fourths the size of those of H. Ewingii; the 
parotics project much further outwards, and are considerably narrower. 
The tegmen cranii reaches more than half-way from the foramen magnum to the 
front of the cavity, and runs round the single fontanelle (fo.) as a considerable band 
both right and left and in front. The greatest width of this membranous space is 
equal to that of 11. Evnngii and to its own length, but the widening backwards of the 
marginal tegmen makes it lose what would otherwise be the circular form. 
A large triangular tract of cartilage exists above, occupying most of the hinder 
tegmen, and a clear synchondrosis exists both above and below at the foramen magnum 
( fm .); the floor of the vestibule and the tegmen tympani (fig. 7, vb. , and fig. 6, t.ty.) 
are also unossified. Above, there is a narrow tract of cartilage running from the 
horizontal canal to the junction of the anterior and posterior canals (fig. 6). In front, 
the prootic bone reaches to the foramen ovale (fig. 7, V.); above (fig. 6), the bone 
reaches the roof over the optic fenestra (II.) The girdle-bone ( eth .) only occupies one- 
z 2 
