ORDER IX PTEROSAUKIA 247 



axis extemling nearly at right angles with the neck Invesfing hones of temporal 

 region contracting into an upper and a lower arcade ; sutures becoming obliterated in 

 the adult. Quadrate large, firmly fixed ; orbit very lavge, and usually with sclerotic 

 ring ; antorbital vacuity large, sometimes confiuent with external nares. Teeth, when 

 presenf, slender, conical, thecodont, and confined to margin of the jaws. Mandibular 

 rami fused at the Symphysis. Presacral vertebrae procoelous, caudals amphicoelous ; 

 sacrals four to seven in nurnber, usually fused. Cervical and anterior dorsal ribs double- 

 headed. Sfernum large, clavicular elements waiding, scapula ano^ coracoid long and 

 slender. Fifth digit of manus enormously elongated aiul reflexed to support the wing 

 membrane. Pubis excluded from the closed acetabulum. Both rows of tarsals ossified, 

 the astragalus sometimes fused with the tihia, Two to four digits of the pes bear claws, 

 the fifth digit sometimes vestigial. Abdominal ribs present ; no dermal armour. 



The Pterosauria or Ornithosauria, as they are also called, constitute an 

 extraordinary group of extinct reptiles, rangirjg from the Lias to the Upper 

 Cretaceous. They are remarkably bird-like in general appearance, and 

 their whole Organisation is modified for the accomplishment of fiight through 

 the air. In the larger nurnber, however, the power of fiight was more limited 

 than in birds, and may have been in many forms feebler than in bats. The 

 skeleton was more or less pneumatic, like that of birds, and the general 

 avian appearance was accentuated by the articulation of the head at right 

 angles to the cervical axis. Some of these bizarre creatures were no larger 

 than sparrows, but others, with whose extinction the history of the race 

 terminates, were of gigantic size, the spread of their cutaneous expansion 

 being nearly 6 m. from tip to tip. 



The vertebral column comprises seven true cervicals, twelve to sixteen 

 dorsals, four to seven sacrals, and ten to forty caudals. The presacral vertebrae 

 are procoelous, and the caudal amphicoelous. The neural arches are usually 

 fused with their centra, and the sides of the latter are more or less extensively 

 hollowed. Cervical ribs, when present, are very much shorter than the dorsal 

 ribs. The latter are double-headed anteriorly, but become single-headed and 

 more slender toward the sacral region. Transverse processes are very strongly 

 developed in the anterior sacral vertebrae. There is a triple series of small 

 V-shaped abdominal ribs along the ventral wall of the body cavity. 



The sJmll (Fig. 352) is remarkably bird-like in form, and its constituent 

 elements usually become anchylosed at an early age. The orbits are very 

 large, laterally placed, and surrounded by a sclerotic ring of small plates. An 



p. 63), 1831. — Hvxley, T. H., On Rhampliorhynchus Bucklandi (Quar. Jouni. Geol. Soc. vol. XV. 

 p. 658), 1860. — Marsh, 0. C, Various articles in Amer. Journ. Sei. [3], 1871-84 (vols. I. p. 472 ; 

 III. p. 241 ; XI. p. 507 ; XII. p. 479 ; XVI. p. 233 ; XXI. p. 342 ; XXIII. p. 251 ; XXVII. p. 

 423, etc.). — Meyer, U. van, Reptilien aus dem lithographischen Schiefer (Faunader Vorwelt, pt. IV.), 

 1860. — Xewton, E. T., On the skull, brain, and anditory organ of Scaphognathus purdoni (Phil. 

 Trans, vol. CLXXIX. B, p. 503), 1888.— Notes cn Pterodactyles (Proc. Geol. Assoc. vol. X.), 1888. 

 — Owen, Tl., Reptilia of tlie Liassic Formations ( Palaeontogr. Soc. pt. II.), 1863. — PUeninffer, F., 

 Campylognathus Zitteli (Palaeontogr. vol. XLT.), 1894.— Beiträge zur Kenntniss der Flugsaurier 

 {ibüi. vol. XliVIII.), 1901.— Qnenstedt, F. A., lieber Pterodactylus suevicus. Tübingen, 1855. 

 — Seeley, H. (r., The Ornithosauria, Cambridge, 1870. — On the Organisation of the Ornithosauria 

 (Journ. Linn. Soc. vol. XIII.), 1884.— The Ornithosaurian pelvis (Ann. Mag. Nat. Hist. [6], vol. 

 VII. p. 237), 1891. — On the shouMer-girdle in Cretaceous Ornithosauria (iä/(/. p. 438).— Dragons 

 of the Air, London, 1901. — Wagner, A., Contributions on Upper Jurassic Pterosaurs in Abhaudl. 

 Bayer. Akad. Wissensch. math.-phys. Classe, vols. II. p. 163; VI. pp. 129, 690; VIII. p. 439 

 (1837-58). — WilUston, Ä W., On the skiül of Ornithostoma (Kansas Univ. Quar. vol. IV. p. 195), 

 1896. — Restoration of Ornithostoma (Pteranodon), {ibid. vol. VI. p. 35), 1897. — Zittel, K. A., 

 Ueber Flugsaurier aus dem lithograpliischen Schiefer (Palaeontogr. vol. XXIX. p. 49), 1882. 



