DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 107 



it is a very long, naiTow leaf of cartilage, and lies in a recess of tlie ethmoid, nearly 

 touching the wing ; its fore edge is ribbed. 



The mandible {ink) is a thick, short, chubby cartilage — like a little short ulna; the 

 lower labial (l.l.) meeting its fellow by a bi'oad face, is thick and strong ; and the 

 temporary upper labials {u.l.) are thin erescentic leaves of cartilage. 



The hyoid bar (fig. 7, c.hij.) is normal ; above, there is the sinuous condyle, and the 

 rudimentary styloid process ; and ventrally it is dilated largely — most beliind — and 

 then suddenly less, it becomes the basi-hyal ; this is composed of simple cartilage. 



This chondrocranium is essentially like that of the youngest Psemlis, another 

 member of tlie Cystignathida3 (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, tnpartite 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 rudimentaiy ; no " inter- " or " supra-stapedial." 

 1 0. Vomers rudimentary and toothless. 



Seventh genus. — Cyclorhamphus. 



27). Ci/vlorhamphtis marmoratus. — Adult female ; l| inch long. Vinco Caya, Peruvian 

 Andes; height, 16,000 feet. 



This is a stout, evenly semi-oval, short .skull (Plate 20, figs. 1-G) ; the length is to the 

 breadth a.s 6f to 8. The quadrate condyles only reach opposite to the middle uf 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 iia.sal roofs short, the vomers small, and the inner 



p 2 



