The singular articulation for the humerus at the truncated extremity of the coracoid bone is a character of this group, as is the articulation of the scapulæ with the neural arches of the dorsal vertebræ, at right angles to them (p. 115), instead of running over the ribs as in Birds and as in other Pterodactyles. The smaller Pterodactyles have their jaws less compressed from side to side. The upper arm bone, the humerus, instead of being truncated at its lower end as in Ornithocheirus, is divided into two or three rounded articular surfaces. That for the radius, the bone which carries the wrist, is a distinct and oblique rounded facet, while the ulna has a rounded and pulley-like articulation on which the hand may rotate. These differences are probably associated with an absence of the remarkable mode of union of the scapulæ with the dorsal vertebræ. But I have hesitated to give different names to these smaller genera because no example of scapula has come under my notice which is not truncated at the free end. I do not think this European type can be the Nyctodactylus of Professor Marsh, in which sutures appear to be persistent between the bodies of the vertebræ and their arches, because no examples have been found at Cambridge with the neural arches separated, although the scapula is frequently separated from the coracoid in large animals. [Illustration: FIG. 71. UPPER AND LOWER JAWS OF AN ENGLISH PTERODACTYLE FROM THE CHALK, AS PRESERVED] ORNITHOSTOMA [Illustration: FIG. 72. THE PALATE OF THE ENGLISH TOOTHLESS PTERODACTYLE, ORNITHOSTOMA] [Illustration: FIG. 73. TYPES OF THE AMERICAN TOOTHLESS PTERODACTYLE, ORNITHOSTOMA Named by Marsh, Pteranodon]