4G 
MR, W. K. PARKER OK THE STRUCTURE AKD 
this is greatly in contrast with what is seen in jR. pygmcect, for it has, like many other 
small Batrachians, very little condyles, very wide apart. 
The lower face of the occipito-auditory mass runs across at exactly a right angle to 
the axis of the skull, but when its whole extent is seen from above its outer angles 
are seen to be bent forwards.'" 
This lower face, from one “ stylo-hyal” to the other, is a broad tract, one-third 
longer and one-third broader than the straight and almost evenly oblong interorbital 
region. The prootics and ex-occipitals ( pr.o ., e.o .) of the same side are confluent, but 
there is a distinct synchondrosis both above and below (figs. 1, 2). A slight edge of 
cartilage remains to the floor of the tympanum, and a larger tract to its “teg-men” 
(fig. 3) ; nevertheless the ossification is intense, and reaches in front within a short 
distance of the optic foramen (II.). Also the girdle-bone is more than twice as 
extensive as in the medium type; it abuts upon the optic passage behind, and besides 
the whole ethmoid, with its outer wings, runs half way along the proper nasal roof, 
floor, and middle wall (figs. 1, 2, and 3). 
A small superorbital projection can be seen over the inner can thus ; these, and the 
wings of the ethmoid, up to the point where segmentation takes place in Bufo, are 
ossified. 
As to the fore and middle parts of the endocranium, we see some curious results 
of overgrowth. First, the cranial “barge” appears to be very small and contracted as 
compared with the huge arches of the facial outworks; and, in the second place, the 
nasal labyrinth is greatly exposed by the retirement from it of the facial arches, in 
their wide sweep outwards. In the smaller kinds (see Plate 6, figs. 6 and 7) the nasal 
labyrinth is carefully packed between the laminae of the premaxillaries and maxillaries. 
In the upper view (fig. l) we see the nose lying naked, for the most part, between 
the bony boundaries; the outer angles of the floor ( c.tr .) lying on the palatine lamina 
of the maxillaries. but not hidden by the upper plate. The ascending part of the 
outer angle of the floor (fig. 3, n.iv.) is considerably ossified ; it reaches the roof ( al.n .) 
above, and coalesces with it. There is a “prenasal rostrum” (in front of s.n.) of 
moderate size, and large subretral pro-rhinals (p.rh.) ; the labials {u.l 1 ., id 3 .) also are 
well developed round the circular aperture ( e.n .). 
The cartilaginous palato-quadrate arch, on each side, is almost eaten away by the 
ectosteal palatine and pterygoid {pa., Jpg.), the one thick and spatulate, the other a 
strong triradiate bone.t 
* In the lower view (fig. 2) I have only figured the parts that come immediately under notice; the 
distant upper parts are left out, as they are not necessarily seen by the eye when discriminating the lower 
surface. The upper view must be compared with this to get a complete idea of the form. 
f In this and in a large number of Batrachia these two bones are as truly ectosteal as the sheaths of the 
columella or of the thyro-hyal, and become truly homologous with the periehondrial laminae of the prootic 
exoccipitals and sphenethmoid. I therefore colour them, throughout, as endoskeletal bones. In the 
“ Shoulder, girdle” we see the same temporary distinctness of the periehondrial, from the endosteal tracts of 
bone, in the “pro-coracoid” and “ supra-scapula.” (See my “ Shoulder-girdle and Sternum,” Plates 5-7.) 
