DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
259 
Certainly, in many of the Anura, more or less cartilage appears in the outer edge of 
the hyoid bar, but quite distinct from it, corresponding exactly to the basal part of 
the pectinated inter-branchials of the hyoid, bar in the Shark and. Chimcera. 
The hyoid, bars, the soft bqsi-hyal, the rudimentary cerate - branch ia Is, the paired 
hypo-branchials, and the median basi-branchial all fuse together to become the hyo- 
branchial apparatus of the adult. The narrowed and ossified hypo-branchials are true 
“ thyro hyals,” like those of the Mammal. 
Among the newly appearing parts are the stapes {early), and the columella (late). 
The stapes appears about the time of the first bony tracts; but the columella, as a rule, 
not until some months after metamorphosis. It appears whilst the tail is still large in 
Pseudis; and long before hatching in Pipa; in Dactylethra it is as late as in the 
ordinary “ Phaneroglossa.” 
E .—The normal (or Ranine) adult skull compared with sub-typical and aberrant forms 
in the “ Anura,” generally, 'where larval structures are in some degree retained, or 
where generalised ( ichthyic ) characters turn up; lastly, the residuum of characters 
which are universal. 
The prootics (or spheno-prootics) and ex-occipitals are not separately ossified, as 
in the “ norma,” in Pseudis, Dactylethra, and others. In some kinds, as Acns, Pseudo- 
phryne, Diplopelma, there is a small basioccipital; in some of these small kinds there 
is an evident endosteal super-occipital. 
The girdle-bone is absent in some dwarf kinds, as in some small West African Ranee, 
in Gomphobates, and in some species of Diplopelmai. 
The girdle-bone is in two pieces in Diplopelma ornatum, in Engystoma, and in 
Pseudophryne; there is a large X-shaped, persistent membrane bone over the eth¬ 
moidal region in Dactylethra, a crescentic bar in Rappia bicolor, and a similar bone, 
not persistent, in Rana temporaria. 
As a rule, there are two lesser fontanelles over the hind skull besides the main 
space, but in many kinds there is only the large one; in Alytes there is one lesser, 
hinder fontanelle. 
In some of the Frogs (Rana, sp.), still better in the Hylidse, there is a superorbital 
“ eave ” of cartilage; in Phyllomedusa bicolor, Hyla rubra, and especially in Alytes 
obstetricans, there is a separate superorbital cartilage, besides. 
The nasal region is often largely ossified from the girdle-bone; this tract may be a 
true “ sphenethmoid,” as in Dactylethra, where it does not finish the ethmoidal region 
in front, but runs back to the auditory capsules. 
The nasal roofs are only partially covered by their own proper cartilage in the genus 
Bufo, in Dactylethra, and in some others ; the pro-rhinals are distinct in Rana esculenta 
and in Dactylethra ; the two nasal fenestrse of Bufo answer to the series of slits in 
Myxine. 
In Bufo vulgaris and some other species of that genus (not in B. ca.lamita) the 
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