In certain Pterodactyles the proximal condyle of the femur resembles birds; but in other Pterodactyles the bone is more mammal-like in its straightness, and development of the upper condyle, and in the presence of a trochanter.
may be compared, from their great length, with birds and flying vertebrate animals.
The fibula is style-shaped, like that of a bird, the lower part being wanting; while in bats the upper part is wanting.
of two rows, is best compared with that of reptiles. The number of constituent bones has not been definitely determined.
shows a certain return from the bird type to that of reptiles.
Von Meyer never finds more than four toes, and sometimes a stump of a fifth. As a whole, the foot is Saurian-like. It differs from lizards in the number of toes, and approximates to Crocodiles. In Pterodactylus longirostris the formula of the toes is 2, 3, 4, 5, with a stump of two joints;--like lizards, if we abstract the outer toe; and like birds with four toes; but they are liable to variations.
In Pterodactylus scolopaciceps and P. Kochi the formula is 2, 3, 3, 4 joints. In Winkler's specimen of P. Kochi there is also a stump of three joints.
In Pterodactylus micronyx the formula is 2, 3, 3, 3, and a stump of two joints. In P. longicollum the number appears to be different from all the foregoing.
The stump was attached to the side of the outer toe. Wagner, in P. Kochi, supposed it to be on the inner side, and so gave a reverse arrangement to the toes. The stump may be compared with that of some Chelonians, in which it is not furnished with a claw.
There is a difference from birds in the claws being much less developed. It has a true reptile foot. In bats the toes are of equal length. Von Meyer thinks the hind-legs did not enable it to walk on the land.
In some Pterodactyles the flying-membrane is faintly seen. The presence of feathers might be inferred from there being but one finger for flighty as in birds; but the function of feathers is subserved by the long and stiff finger. If it had been covered with scales, as was supposed by Cuvier, some traces of them would be found. The skin was probably naked, and had no connection with the hind-legs as it has in bats; in this respect resembling birds.