108 -sm. W. K. PARKER ON THE STRUCTURE AXD 



nostrils mucli nearer tosjether — asfainst rule — than the outer. This is one of the 

 lowest and most generalised of the Ranidse. 



The occipital condyles (Plate 20, figs. 1, 2, oc.c.) are large, oval, and postero-inferior ; 

 they are separated by a concave notch of their own width. The whole hind skull has 

 a remarkable form, for the auditory capsules are very large and thoroughly ossified, 

 yet the canals project very much both before and behind, pushing the epiotic eminence 

 almost as far back as the occipital condyles, and the anterior (prootic) swelling, caused 

 by the anterior canals, into the orbital region. The parotic projections suddenly 

 become one-half the size of the main capsule and are only one-third at the teginen 

 (fig. 1). The extreme edge of this part (inside sq.) is unossified, and there is a small 

 semi-osseous tract in the superoccipital region ; all the rest of the endocranium is 

 ossified up to the middle of the nasal septum (fig. 2, eth.) below, and still further 

 forwards above (fig. 1, s.n.). 



Moreover, the parasphenoid behind, and the fronto-parietals for fully two-thirds of 

 their extent, are anchylosed to the bone within. The temporal fossae are deep rounded 

 hollows ; the orbital region of the skull, from thence, swells gently, and then remains 

 of the average width up to the antorbital bars ; then there is a sHght superorbital 

 projection, but it also is ossified. 



The tegmen of this hard endocranium is extensive before, but more so behind ; for 

 that tract reaches so far as to lie over the front edge of the optic fenestra (II.). The 

 edges of the open part are wide, so that the single fontanelle (/'>•) is only one-fourth 

 the length of the ci-anial cavity, and is narrow, and pinched in the middle. Here the 

 roof is almost covered in, as in some old Skates' skulls. 



The girdle-bone, as in some Salamanders, is not marked ofi" behind ; in front it runs 

 far forward into the true nasal region, and right and left, ossifies the ethmoidal wings, 

 but stops at the ethmo-palatines (fig. 1, e.pa.) exactly where the segment is in the genus 

 Bufo. The nasal region [n.r.) is very remarkable, being, like that of Bomhinator 

 (Plate 25, fig. 1), merely a transverse double pouch ending in a broad sub-arcuate 

 snout, which is scarcely covered by the nasals, which lie mainly on the proper ethmoidal 

 tract. Hence the outer nostrils {e.n.) are very wide apart; but the floor being very 

 narrow where the trabeculge originally came first into contact in the internasal region 

 the inner nostrils (fig. 2, i.7i.), although large and round, are very near together for a 

 Batrachian ; the relative distances are exactly reversed in this case. 



The roof {n.r.) is narrow from the ethmoid onwards, but the nasal wall (fig. 1) 

 forms a pouch behind the outer nostril. The inner labial (i/J'.) is small, and lies 

 against the front of the broad snout; the outer piece (».P.) is in front of the nostril. 

 Below (fig. 2), the trabeculae in becoming the floor have scarcely changed their form 

 at all ; but they have budded out into a pair of large falciform, secondary cornua at 

 their inner angle ; these are the pro-rhlnals {p.rh.). 



The palato-suspensorials are normal in the palatine region, and the bone {pa.) is of 

 the usual y-shape ; it forms but little union -with the cartilage. 



