With the possible exception of small paired or median cartilages inserted between the inner extremities of the basipterygia in _Polypterus_ and a few other Teleostomi, the pelvic girdle is absent in all the existing members of this group, having either become completely suppressed, or remaining unseparated from the basipterygia of the pelvic fins.[217] In the Dipnoi (Fig. 144) there is a true pelvic girdle which has some points of resemblance to that of certain of the caudate Amphibia. It is represented by a median, lozenge-shape, cartilaginous {242}plate, produced in front into a long tapering epipubic process, and on each side of this into a forwardly inclined prepubic process. The hinder part of the plate bears two short processes for the basal cartilages of the pelvic fins. There is no trace, however, of iliac processes. THE PECTORAL FINS.—The skeleton of the pectoral fins exhibits remarkable structural variations in different Elasmobranchs. In the existing members of the group two large basal cartilages, the propterygium and the mesopterygium, are formed by the concentration and fusion of the proximal portions of certain of the preaxial radialia, and they, with the metapterygium, articulate with the pectoral girdle; hence the fin is tribasal as well as uniserial (Figs. 141 and 146, A, B). In striking contrast to all other Elasmobranchs the pectoral fin of _Cladoselache_ (Fig. 145, A) is far more primitive than in any other Fish. Each fin is supported by a distal series of slender, more or less parallel, unjointed, cartilaginous radialia, and basally by a similar series of shorter, stouter, and less numerous cartilages, which apparently were imbedded in the body-wall, the entire fin skeleton presenting a striking resemblance to an isolated median fin in which the supporting radialia have concentrated by growth pressure, and their proximal portions have been reduced in number by partial fusion.[218] _Pleuracanthus_, on the other hand, had a biserial fin, the preaxial and postaxial radialia supporting fan-like clusters of horny fibres at their distal ends (Fig. 250). [Illustration: FIG. 145.—A, Pectoral fin, and B, pelvic fin of _Cladoselache_. (From Bashford Dean.)] {243}[Illustration: FIG. 146.—Pectoral fins of various Fishes. A, _Acanthias vulgaris_; B, _Raia sp_.; C, _Chimaera monstrosa_; D, _Acipenser rhynchaeus_; E, _Amia calva_; F, _Lepidosteus platyrhynchus_; G, _Polypterus bichir_; H, _Salmo salvelinus_. The preaxial side of each fin is to the left and the postaxial to the right. _f.r_, Dermal fin-ray; _ms_, mesopterygium; _mt_, metapterygium; _p_, propterygium; _r_, free radialia; 1, 5, the preaxial and postaxial basal elements in a Teleost, which may be mesopterygial and metapterygial pieces respectively, the three remaining basal pieces probably being intrusive metapterygial radialia directly articulating with the pectoral girdle. In B, D, E, and F, similar intrusive radialia are shown. (From Gegenbaur.)]