242 
MR. W. K. PARKER ON THE STRUCTURE AND 
there is a small bony basi-branchial (b.br 1 .). The thyro-hyals (t.hy.) are normal, they 
are long, straight, and moderately divergent. 
The mandible (fig. 9) is normal, but there is some endosteal deposit in the hinge. 
The investing bones are very thin, but are dense, smooth laminae; the fronto-parietals 
(fp.) are separate ; the two form a roughly pentagonal tract, they cover the hind skull 
largely, partly overlapping the canals, and well overlie the wide roof-space ; their nasal 
suture is nearly transverse. The nasals (n.) are broad elegant shells of bone, showing 
the vascular rate through their thin clear substance; they meet along the middle, 
and send a curved horn over the sub-tubular nasal passage, in front, and another 
downwards, behind, to join the maxillary. 
The premaxillaries, maxillaries, and quadrato-jugals (px., mx., q.j.), are narrow, and, 
relatively, feeble bones; the squamosal (sq.) is very small, has an uncinate postorbital 
process, and binds merely on the anterior part of the small tegmen tympani ( t.ty .). 
The only other Batrachian known to me with a parasphenoicl equal to this is Pipa; 
it is more like that of the “ Urodeles ” (Phil. Trans., 1877, Plates 24-26). It stretches 
from near the foramen magnum, to opposite the ethmoidal axillae, and the width is 
such as nearly to reach the foramina ovalia (V.) ; it then expands in lozenge-shaped 
processes under the ear-capsules; the narrowing of the fore part takes place gently, 
and there the bone is like a (relatively) large spoon. The vomers (fig. 8, v.), on the 
contrary, are mere crescentic films of bone, bounding the inner edge of the internal 
nostrils ( i.n .). 
As compared with the “ norma,” this skull is— 
1. Very small and arrested, the face being feeble, and the cranial cavity very large, 
relatively. 
2. There are endosteal rudiments of the keystone and threshold bones—basi- and 
supraoccipitals. 
3. The bones of the hind skull are generalised, or continuous on the same side. 
4. The moieties of the girdle-bone are wide apart, and run into the palatine region, 
ossifying the cartilage, and suppressing the normal bony plate. 
5. There is a distinct prenasal rostrum. 
6. The parts of the middle ear are only feebly developed, and the stapes is a hollow 
semi-osseous shell. 
7. The hyo-branchial apparatus is solid at its attachment, has an extra-hyal 
cartilage, is sub-crescentic, and possesses a distinct basi-branchial bone. 
8. The roof- and floor-bones are very wide, the marginal bones narrow, and the 
vomers extremely minute ; there are no septo-maxillaries. 
