DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
235 
The want of symmetry mentioned above is best seen in the roof-bones (fig. l,f.p., n.). 
Large as are the fronto-parietals, they barely cover the two lesser fontanelles, behind, 
and there is an open chink in front. In their hind third they are anchylosed; their 
angular postorbital projections are not opposite, the left is in front of the right, and 
their jagged fore part shows the same asymmetry ; tlieh' orbital edge is sharp and 
separated from the rest by a sub-marginal fossa; there is a good space between these 
bones and the nasals, leaving the girdle-bone naked : the orbital plate (fig. 3, fp-) is 
definite, but narrow, less than a third the depth of the shallow skull-basin. The left 
nasal (n.) does not go so far back or so far inwards as the right; it is only three-fourths 
the size of the latter; contrary to rule, the nasal, broadening outside, lies right down 
on the top of the maxillary (fig. 3, n., mx.), leaving only a little chink in front. The 
nasals are (relatively) thick, convex shells; they are not entirely free from the 
subjacent endoskeletal bone ( etli .). They are round in front, a good space apart, and 
leave the Anatine snout uncovered. 
The premaxillaries ( px. ) run across under the snout, and meet at a large angle ; 
they have pointed palatine processes (fig. 2), and short, tilted nasal processes (fig. 3). 
The maxillaries (mx.) are of the average size, and only become pointed near their 
end; their sharp edge has a narrow palatine plate growing from it (fig. 2). 
The quadrato-jugals (q.j.) are small, short, curved bones, slightly connected with 
the suspensorium ( q .), and only touching the end of the maxillary. The squamosals 
(sq.) are in this species very instructive ; they might be described as “ preoperculars,” 
bent the wrong way: a thing not impossible, for the outer bony plates are brought 
under the power of the endocranium to a very remarkable extent, and “ without 
hands,” are moulded upon it, cunningly. 
In this species the supratemporal part of the bone is very narrow, and only clamps 
the edge of the unossified “tegmen,” ( t.ty.); Moreover, the axis of the supratemporal 
region is coincident with that of the stunted postorbital; the short descending part 
bends itself backwards at a very obtuse angle; this is the rounded space against, and 
partly on which, the small “annulus” (a.ty.) lies. 
The parasphenoid (fig. 2, pa.s.) is a very remarkable bone, it is almost all “ wings; ” 
measured to the mid-line they are larger than the scoop-like fore part; they are also 
broader, and are obliquely truncate outside. Between these wings there is a fore¬ 
looking, triangular spur, as large as the hinder projection of the bone. The bone falls 
far short of the middle part of the ethmoid, in front. 
The latter bone ( eth .), in its subnasal extension, shows two sigmoid crests that 
bound the widely severed internal nostrils ( i.n .); these are the anchylosed vomers (v .); 
the right is much larger than the left. 
I shall compare the skull of the three species of this genus with that of the “ norma,” 
together; they differ remarkably inter se; but agree with each other in being almost 
the most abnormal of all the tongue-bearing Anura. 
2 h 2 
