170 MR. W. K. PARKER ON THE STRUCTURE AND 



roofs are small (Hgs. 1 and 4), and the nasal floor large (fig. 2, right and left of s.n.). 

 The end of the septum (s.n.) projects as a triangular rostrum (fig. 4, p.n.), and the paired 

 trabeculse have developed their new horn or pro-rhinal {p.rh.) in such a manner as to 

 almost rival the outer angle of the first horn (fig. 4, c.f.r.) ; that is pedate with the toe 

 outwards : tliis is Uke an adze blade. The outer nostrils (e.n.) are only moderately 

 wide apart ; the inner {i.n.) are not so far apart as in many cases ; they are very large 

 and circular ; the labials (u.V.u.l'.) are normal. The palato-suspensorials are Uke those 

 of a young Common Frog ; they are slender and but Uttle affected by the bony tracts ; 

 have a large cultrate pre-palatine ; and end behind in two massive growths, the 

 condyles of the pedicle and quadrate {pel., q.c.) ; these parts are much hke tho.se of 

 Pelodryas. The Eustachian opening (ew.) in the angle is almost circular and of the 

 average size — only half as large as the inner nostril. The palatines and pterygoids 

 {ixi., pg.) are slender, but quite normal. The mandible (fig. 3) is normal. 



The annulus (figs. 1 and 5, a.ty.) is of normal size, but its horns are wide apart. 



The stapes (fig. 5, st.) is an oval plate obhquely truncated in front ; on it, antero- 

 superiorly, the arched columella fits ; it is equally wide at both ends, has no segmen- 

 tation, and no supra-stapedial cartilage — only a fibrous band [ti.st.). There is no 

 inter-stapedial segment, even marked by ossification, and the bony matter runs up 

 nearly to the stapes. The extra-stapedial [e.st.) is two-fifths the length of the outer 

 rod ; it is a rounded spatula. 



The stylo-ceratohyal is confluent above (fig. 2, st.h.), and gently widens to the 

 middle (fig. 3, c.hy.) ; it then lessens agam, and retiuuis backwards into the basal plate 

 without any hypo-hyal lobe. Only the sharp postero-lateral lobe exists on the short, 

 small basal plate {h.h.hr.) ; the thyro-hyals {t.liy.) ai'e well developed, moderately 

 diverging, and straight. 



The investing bones are such as we shoidd find in a young Pelodiyas equal to this 

 species in size. The fronto-parietals (fig. \, f.p.) form a narrow, straight wall-plate, 

 widened, like a foot, over the temporal fossa ; they turn slightly outwards over the 

 superorbital eave, and inwards, a little behind. The nasals {n.) are narrow crescentic 

 shells, with a spike on the middle of their convex edge. 



The marginal bones {px., mx., q.j.) are well formed and typical, but extremely 

 thin ; I find no septo-maxillary in tliis species. The squamosals {sq.) have a good 

 upper bar, projecting as a free postorbital process m front. 



The parasphenoid (fig. 2, pa.s.) is characteristic of this Family ; it is well formed, 

 wide in its main part, has all its processes pointed, but the basi-temporals are naiTow. 

 The vomers (r.) show notliing of the breadth of those of Pelodryas (Plate 34, fig. 2), 

 nor the radiate character of those of Phyllomedusa (Plate 34, fig. 8); they are quite 

 normal, and have a small obliquely-oval dentigerous plate. 



This skull should be compared \vith that of a young Common Frog of the first 

 autumn ; then we can see that its divergence from the type is in these several pecu- 

 liarities, namely : — 



