[Illustration: FIG. 11.--Hyoid and branchial apparatus of _Necturus maculosus_.
Hh, Hypo-hyal. Ch, Cerato-hyal. Bb^1, First basibranchial. Bb^2, Ossified second basibranchial. Ep.b^1, Ep.b^2, Ep.b^3, First, second and third epibranchials. Gl, Glottis.]
The pelvic arch of some of the Stegocephalia contained a well ossified pubic element, whilst in all other batrachians only the ilium, or the ilium and the ischium are ossified. In the Ecaudata the ilium is greatly elongated and the pubis and ischium are flattened, discoidal, and closely applied to their fellows by their inner surfaces; the pelvic girdle looks like a pair of tongs.
The long bones of the limbs consist of an axis of cartilage; the extremities of the cartilages frequently undergo calcification and are thus converted into epiphyses. In the Ecaudata the radius and ulna coalesce into one bone. The carpus, which remains cartilaginous in many of the Stegocephalia and Caudata, contains six to eight elements when the manus is fully developed, whilst the number is reduced in those forms which have only two or three digits. Except in some of the Stegocephalia, there are only four functional digits in the manus, but the Ecaudata have a more or less distinct rudiment of pollex; in the Caudata it seems to be the outer digit which has been suppressed, as atavistic reappearance of a fifth digit takes place on the outer side of the manus, as it does on the pes in those forms in which the toes are reduced to four. The usual number of phalanges is 2, 2, 3, 2 in the Stegocephalia and Caudata, 2, 2, 3, 3 in the Ecaudata. In the foot the digits usually number five, and the phalanges 2, 2, 3, 3, 2 in the Caudata, 2, 2, 3, 4, 3 in the Stegocephalia and Ecaudata. There are occasionally intercalary ossifications between the two distal phalanges (33). There are usually nine tarsal elements in the Caudata; this number is reduced in the Ecaudata, in which the two bones of the proximal row (sometimes coalesced) are much elongated and form an additional segment to the greatly lengthened hind-limb, a sort of _crus secundarium_. In the Ecaudata also, the tibia and fibula coalesce into one bone, and two or three small bones on the inner side of the tarsus form what has been regarded as a rudimentary digit or "prehallux."