DEVELOPMENT OE THE SKULL TN THE BATRACHIA. 
221 
shows a large triradiate upper part, and a long (deep) sinuous preopercular process 
bound by the “orbitar process,” behind. The parasphenoid (fig. 6, pa.s.) is unlike 
that of the last, it is shortened in front and is there made up of spines ; its basi¬ 
temporal wings are very long, and the pterygoids bind over them so as to cut away 
their fore edge, outside; they then run to a point, almost as far as the Eustachian 
openings (eu.). The hind part is a broad triangle, and in front of it the middle of the 
bone is raised into a triangular apophysis, which looks forwards. The vomers (v.) are 
formed of three curved rays, the two hinder rays half surround the inner nostril (i.n.) 
and the front ray curves in the other direction. 
63 (continued).—(B) Otilophus margaritifer . —Adult female ; 2-f inches long (Hyutl’s 
prepn., Mus. Coll. Surg., Eng.). Brazils. 
This skull, kindly lent to me by Professor Flower, shows to what a degree of 
external modification the Bufonine type may undergo without losing any essentially 
Anurous character. 
In the side view (Plate 38, fig. 1) we see that the height of the squamosal, measured 
at right angles to the basis cranii, is equal to the gape ; in Rana pipiens and Cystig- 
nathus ocellatus, it is only one-thircl ; and that is the normal proportion. 
This is due to two things—to the height of the lateral crest of the squamosal, and 
to the depth of the grooved sigmoid pre-opercular region (figs. 1, 2, sq.) ; it is the 
upper part which has developed so largely since the creature was half grown (see 
fig. 3, sq.). 
The endocranium is now completely ossified behind (fig. 2); but even now half the 
orbital region is cartilaginous (fig. 1, o.s.) ; this part is extremely shallow. The sides 
of the skull are raised all along up to the snout, and the nasal, frontal, and squamosal 
crests ( n.,f.p ., sq.) are all frosted with small bony spikes and knobs ; the latter crest, 
as a large “ ear,” reaching further backwards than the occipital condyle. 
Behind (fig. 2), the parietal part of the roof-bones ( fp.) has lost the suture, and 
the whole plate lies flat across the wide audito-occipital region, partly covering the 
epiotic eminences ( ep.). Where the squamosals join the roof-bones there is a con¬ 
siderable valley, on each side, in the hind skull. The mid skull and the nasal region 
are concave. 
The orbital part of the squamosal (fig. 1, sq.) projects but little from the shaft, only 
reaches half way to the jugum, and points towards the hind part of the facial plate 
of the nasal (n.). The nasal, frontal, and squamosal form three-fourths of an orbital 
ring, which is finished by membrane, below, far above the edge of the maxillary (mx .); 
all the edges are produced or limbate, and concave. A little more ingrowth of the huge 
nasal would have made it equal to the prefronto-nasal of the Chelonian. The pre¬ 
maxillary is a strong bone like a phalangeal segment, and is nearly all nasal process; 
its top carries the valvular labials (u.l l .u.l z .*) Behind this bone, in an interspace formed 
* In fig. 1 the second labial is lettered u.l}. bj mistake, and the line from u.l~. points to a part of the 
nasal wall, 
