It is a remarkable feature in these animals that the middle bones of the foot, termed instep bones or metatarsals, are usually close together, so that the toes diverge from a narrow breadth, as in P. longirostris, P. Kochi, and other forms; but there also appear to be splay-footed groups of Pterodactyles like the species which have been named P. elegans and P. micronyx, in which the metatarsus widens out so that the bones of the toes do not diverge, and that condition characterises the Ptenodracon (Pterodactylus brevirostris), to which genus these species may possibly be referred. Nearly all who have studied these animals regard the singularly short-nosed species P. brevirostris as forming a separate genus. For that genus Sömmerring's descriptive name Ornithocephalus, which he used for Pterodactyles generally, might perhaps have been retained. But the name Ptenodracon, suggested by Mr. Lydekker, has been used for these types.
Some of the largest specimens preserved at Stuttgart and Tübingen have been named Pterodactylus suevicus and P. Fraasii. They do not approach the species P. grandis in size, so far as can be judged from the fragmentary remains figured by Von Meyer; for what appears to be the third phalange of the wing finger is 7½ inches long, while in these species it is less than half that length, indicating an enormous development of wing, relatively to the length of the hind limb, which would probably refer the species to another genus. Pterodactylus suevicus differs from the typical Pterodactyles in having a rounded, flattened under surface to the lower jaw, instead of the common condition of a sharp keel in the region of the symphysis. The beak also seems flattened and swan-like, and the teeth are limited to the front of the jaw. There appear to be some indications of small nostrils, which look upward like the nostrils of Rhamphorhynchus, but this may be a deceptive appearance, and the nostrils are large lateral vacuities, which are in the position of antorbital vacuities, so that there would appear to be only two vacuities in the side of the head in these animals. The distinctive character of the skeleton in this genus is found in the extraordinary length of the metacarpus and in the complete ossification of the smaller metacarpal bones throughout their length. The metacarpal bones are much longer than the bones of the fore-arm, and about twice the length of the humerus. The first wing phalange is much longer than the others, which successively and rapidly diminish in length, so that the third is half the length of the first. There are differences in the pelvis; for the anterior process of the ilium is very short, in comparison with its length in the genus Pterodactylus. And the long stalk of the prepubic bone with its great hammer-headed expansion transversely in front gives those bones a character unlike other genera, so that Cycnorhamphus ranks as a good genus, easily distinguished from Cuvier's type, in which the four bones of the wing are more equal in length, and the last is more than half the length of the first; while the metacarpus in that genus is only a little longer than the humerus, and much shorter than the ulna. The Pterodactylus suevicus has the neck vertebræ flat on the under side, and relatively short as compared with the more slender and narrower vertebræ of P. Fraasii.
FIG. 62. CYCNORHAMPHUS SUEVICUS
Skeleton restored from the bones in Fig. 60
FIG. 63. RESTORATION OF SKELETON CYCNORHAMPHUS FRAASI
SHOWING THE LIMBS ON THE RIGHT SIDE
From a specimen in the Museum at Stuttgart
