Marsh would warrant so much body membrane as the Rhamphorhynchus has been credited with. I have based my restoration (p. 161) of the skeleton chiefly on _Rhamphorhynchus phyllurus._ THE SHORT-TAILED TYPES The Pterodactylia are less variable; and the variation among the species is chiefly confined to relative length of the head, length of the neck, and the height of the body above the ground. The tail is always so short as to be inappreciable. Many of the specimens are fragmentary, and the characters of the group are not easily determined without careful comparisons and measurements. The bones of the fore limb and wing finger are less stout than in the Rhamphorhynchus type, while the femur is generally a little longer than the humerus, and the wing finger is short in comparison with its condition in Rhamphorhynchus. These short-tailed Pterodactyles give the impression of being active little animals, having very much the aspect of birds, upon four legs or two. The neck is about as long as the lower jaw, the antorbital vacuity in the head is imperfectly separated from the much larger nasal opening, the orbit of the eye is large and far back, the teeth are entirely in front of the nasal aperture, and the post-orbital vacuity is minute and inconspicuous. The sternum is much wider than long, and no specimens give evidence of a manubrium. The finger bones progressively decrease in length. The prepubic bones have a partially expanded fan-like form, and never show the triradiate shape, and are never anchylosed. About fifteen different kinds of Pterodactyles have been described from the Solenhofen Slate, mostly referred to the genus Pterodactylus, which comprises forms with a large head and long snout. Some have been placed in a genus (Ornithocephalus, or Ptenodracon) in which the head is relatively short. The majority of the species are relatively small. The skull in _Ornithocephalus brevirostris_ is only 1 inch long, and the animal could not have stood more than 1-1/2 inches to its back standing on all fours, and but little over 2-1/2 inches standing as a biped, on the hind limbs. A restoration of the species called _Pterodactylus scolopaciceps_, published in 1875 in the _Illustrated London News_ in the position of a quadruped, shows an animal a little larger, with a body 2-1/2 inches high and 6 to 7 inches long, with the wing finger 4-1/2 inches long. Larger animals occur in the same deposit, and in one named _Pterodactylus grandis_ the leg bones are a foot long; and such an animal may have been nearly a foot in height to its back, standing as a quadruped, though most of these animals had the neck flexible and capable of being raised like the neck of a Goose or a Deer (p. 30), and bent down like a Duck's when feeding. [Illustration: FIG. 59. RESTORATION OF THE SKELETON OF _PTENODRACON BREVIROSTRIS_ From the Solenhofen Slate. The fourth joint of the wing finger appears to be lost and has not been restored in the figure. (Natural size)]