DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
107 
it is a very long, narrow leaf of cartilage, and lies in a recess of the ethmoid, nearly 
touching the wing; its fore edge is ribbed. 
The mandible (mk. ) is a thick, short, chubby cartilage—like a little short ulna; the 
lower labial (l.l.) meeting its fellow by a broad face, is thick and strong; and the 
temporary upper labials ( u.l .) are thin crescentic leaves of cartilage. 
The hyoid bar (fig. 7, c.hy.) is normal; above, there is the sinuous condyle, and the 
rudimentary styloid process ; and ventrally it is dilated largely—most behind—and 
then suddenly less, it becomes the basidiyal; this is composed of simple cartilage. 
This chondroeranium is essentially like that of the youngest Pseuclis, another 
member of the Cystignathidse (see Plate 2) ; that is the largest , and this the smallest 
larval Frog I know. The larval skulls are, however, very uniform throughout the 
“ Opisthoglossa ;” yet they have non-essential differences that are of great interest. 
The skull of the adult Camariolius is like that of a young typical Frog, several 
months after transformation. 
This is seen in the general lightness of the investing bones—the moderate extension, 
backwards, of the quadrate hinges, and the divided condition of the ethmoid. But 
there are many things that cannot be put down to mere arrest; these are :— 
1. The continuity of the membranous space, above ; only one very large fontanelle. 
2. The extension of the orbital (or optic) fenestra over three-fourths of the wall, in 
that region. 
3. The intensely ossified and generalised condition of the occipito-auditory region, 
right and left. 
4. The very slight and arrested, tripartite state of the elements of the girdle-bone; 
a “ meso-ethmoidal ” rudiment appearing. 
5. An upper and a lower median rudimentary osseous centre in the occipital arch. 
6. No septo-maxillaries. 
7. Extremely rudimentary fronto-parietals. 
8. Quadrate region partly ossified. 
9. Columella rudimentary ; no “ inter- ” or “ supra-stapedial.” 
10. Vomers rudimentary and toothless. 
Seventh genus.— Cyclorhamphus. 
25. Cyclorhamphus marmoratus. —Adult female ; If inch long. Vinco Caya, Peruvian 
Andes; height, 16,000 feet. 
This is a stout, evenly semi-oval, short skull (Plate 20, figs. 1-6) ; the length is to the 
breadth as 6§ to 8. The quadrate condyles only reach opposite to the middle of the 
stapedial plates, the epiotic eminences are almost flush with the occipital condyles, the 
roof is imperfect, and the ossification is intense, and attended with much anchylosis 
behind. 
The ear is imperfect and the nasal roofs short, the vomers small, and the inner 
