The pteroid bone.
Von Meyer regards it as having supported the wing-membrane in flight. There has been a good deal of difference of opinion about it, some thinking it, with Quenstedt, an ossified tendon; others, like Wagner and Burmeister, regarding it as an essential part of the Pterodactyle skeleton. Von Meyer regards its extent as indicating the extent of the wing-membrane. See p. 42.
Metacarpus.
In length the metacarpus resembles that of the Ruminants, in which however it consists of but one bone; while in Pterodactyles there is a separate bone for each of the four fingers; they are closely united together without being blended. In some Pterodactyles the metacarpals of the short fingers are as fine as hairs, so that it is impossible that they should have articular facets on the carpus. In Ornithopterus the metacarpus has some resemblance with that of the bird, but the articulation with the phalanges of the finger for flight is stiff. In Pterodactylus and Rhamphorhynchus there is a free articulation.
Burmeister remarks that the chief articulation of the wing in bats is with the carpus, while in Pterodactyle the articulation is with the end of the metacarpus.
The hand.
Von Meyer finds four fingers. It was formerly supposed that the order of the phalanges was 2, 3, 4, 4, but in the fly-finger this is not the case, Ornithopterus having but two. The number of joints in the other fingers is quite as irregular.
In Pt. longicollum the thumb consists of but one joint.
The Ilium
is more mammalian and avian than reptilian.