280 



ZOOLOGY 



SECT. 



(Pt), and the palatine, when distinct, bears teeth. The sus- 

 pensorium is inclined forwards, as in the Tadpole, not back- 

 wards as in the adult Frog. The hyoid arch is large, and 

 dorsal end may be separated as a hyomandibular. There 

 three or four branchial arches which are large in the perenni- 

 branchiate forms, but undergo more or less reduction in caducibranch 

 species never, however, forming such a simple tongue-bone as that 

 ^he Frog. The stapes has no columella attached to it, and in 

 correspondence with this there is no tympanic cavity or membrane 



A r d 



ATT 



--Cent 



Cocc Osp 



FIG. St3.-Salamandra atra. The skull. A, from above ; B, from below In bo 



membrane bones are removed on the right side of the figure. Af, antorbital process- 4* 

 d ; Bp, basal plate ; Can, nasal cavity ; Ch. posterior nares ; Ci, process of intemasai 

 plate ; Cocc occipital condyles ; I), aperture of lacrymal duct ; .F. frontal ; Fl oliactorv fi r- 

 men; For. fenestra ovalis; IN. internasal plate ; L,t. ligament connecting stapes with si's 

 pensormm;V maxilla; N. nasal ; Na. nasal aperture ; NK, olfactory SUJ^TSufiS 

 capsule; Ot>, sphenethmoid ; 0*p, supra-occipital region ; P, parietal ; Pa, ascending process nf 

 juspensnrmm ;* pedicle -Pf. pre-frontal ; Pm *. pre-maxilla : Pot. otic jSSSfSjSS 

 urn Pj). palatine process of maxilla ; Ps. parasphenoid ; Pt. pterygoid bones Ptc pterygoid 

 lage ; Jit , im-amen _for nasal branch of trigeminal ; Qu. quadrate; S</ t >. squamosalfs* 

 ; \ /op. vomero-palatine ; Z, process of intemasal plate ; V triffeminai 

 foramen ; J //, facial foramen. (From Wiedersheim's Co^mmtlve Anatomy^ 



111 the Anura there is a very wide range of variation in the 

 skull. Among, the most important points are the presence, in a 

 few species, of small supra- and basi-occipitals, and the fact that in 

 others the roofing membrane-bones are curiously sculptured and so 

 strongly developed as to give the skull a singularly robust ap- 

 pearance. 



In the Gymnophiona (Fig. 894) very little of the original car- 

 tilage remains in the adult state, but the membrane bones are 

 very large and form an extremely complete and substantial 

 structure, especially remarkable for the way in which the small 



