The type of the genus Pterodactylus is the form originally described by Cuvier as_ Pterodactylus longirostris_ (p. 28). It is also known as _P. antiquus_, that name having been given by a German naturalist after Cuvier had invented the genus, and before he had named the species. There are some remarkable features in which Cuvier's animal is distinct from others which have been referred to the same genus. Thus the head is 4-1/2 inches long, while the entire length of the backbone to the extremity of the tail is only 6-1/2 inches, and one vertebra in the neck is at least as long as six in the back, so that the animal has the greater part of its length in the head and neck, although the neck includes so few vertebræ. Nearly all the teeth--which are few in number, short and broad, not exceeding a dozen in either jaw--are limited to the front part of the beak, and do not extend anywhere near the nasal vacuity. This is not the case with all. In the species named _P. Kochi_, which I have regarded as the type of a distinct genus, there are large teeth in the front of the jaw corresponding to those of Pterodactylus, and behind these a smaller series of teeth extending back under the nostril, which approaches close to the orbit of the eye, without any indication of a separate antorbital vacuity. On those characters the genus Diopecephalus was defined. It is closely allied to Pterodactylus; both agree in having the ilium prolonged forward more than twice as far as it is carried backward, the anterior process covering about half a dozen vertebræ, as in _Pterodactylus longirostris_. A great many different types have been referred to _Pterodactylus Kochi_, and it is probable that they may eventually be distinguished from each other. The species in which the upper borders of the orbits approximate could be separated from those in which the frontal interspace is wider. [Illustration: FIG. 60. CYCNORHAMPHUS SUEVICUS FROM THE SOLENHOFEN SLATE SHOWING THE SCATTERED POSITION OF THE BONES _Original in the Museum at Tübingen_] [Illustration: FIG. 61. CYCNORHAMPHUS SUEVICUS RESTORATION SHOWING THE FORM OF THE BODY AND THE WING MEMBRANES]