(1) Brongn iart, " Insectes fossiles des temps primaires," published by Theolier et Cie. Paris, 1894.

(2) Handl irsch, " Einigo intercssan te Kapitel der Palao-Entomologie/ ' Bericht de Sektion fur Palaontologie und Abstmnmungslehre, of 20th April and 18th May, 1910, pubfoihod in Verhandl ungen der K.K. Zoologisch-Botanisch Gesellschaf t in Wien, pp. 160-185.

(3) Ahel, " Fossile Flngfische," ('-Hihrbuch der K.K. Geologische Reichs Anstalt for 1B06, Vol. 56 , pp. 1-88, 1908).

(4) Carnhridge Natural History, Vol. VII., 1904, pp. 701-702.

(5) Jordan , " C uido to the Study of Fishes " ( Hott & Co., New York, 1905), Jordan and Evermam1, " Fishes of North America," Bulletin No. 47 of United States National Mrn•mum, p. 730. Moebins, " Die Bewegnngen rlcr ftiegenden Fische durch die Luf t " (Zeitschrif t Wissmseh Zoologie, Vol. XXX., Suppl., 1878, p. 342). A. v. Humboldt, "Heise in die Aequinoctialgegenden des ncuen Continents," Stutt­ gart, 1815, p. 307. A. Seitz, "Das Fliegen der Fische " (Zool. Jahrbucher. Abt. f . Syst., Vol. V., Jena, 1891, p. 361). F. Dahl, "Die Bewegung der fliegenden Fische durch die Luf t " (Zool. Jahrbucher. Abt. f. Syst., V., Jena, 1891, p. 679). F. Ahlborn, " Der Flug der Fische " ( Zool. Jahrbucher, Abt. f . Syst., Vol. IX, Jena, 1897, p. 329).

(6) More than one observer has noticed that the flapping is more easily seen when the observer is nearly on a level with the water. Ignorance of this fact may explain some of the contradictory opinions that have been formed.

(7) Durnford, " Flying fish flight, and an unfixed law of nature " (Annals and Magazine of Natural History. seventh series, 1906, Vol. 17, p. 15&). Also " The flying fish problem," in the same magazine, Vol. 18, p. 334.

(8) H. Seeley, " Dragons of the air " (Methuen ).

(9) This species of pterosaur had a rhomboidal membranous expansion at the tip of the tail. It was supported by processes arising from the upper and unde:r surfaces of the vertebrae. That is to say, in flight it extended in the vertical plane, and may have been used for steering from side to side. It appears unduly small for such a purpose, and it has been suggested that it was used for steering while the animal was in the water. Possibly the animal had a habit of flapping over the surface with its tail immersed.

(10) 0. C. Marsh, " The wings of Pterodactyles " (Geol. Magazine ( 2), Vol. IX., 1882, p. 205).

(11) Huxley, "On the animals which are most nearly intermediate between birds and reptiles " (G eol. Magazine, 1868, Vol. V., p. 357 ).

(12) Zittel, " Grundziige der Palaeontologie," Vol. II., 1910.

(13) A cast of a perfect skeleton of Iguanodon may be seen in the Reptile Gallery of the Zoological Department at the Natural History Museum, South Kensington, Remains of most of the animals mentioned in this paper may be seen at this museum, and are well worth the attention of readers who may wish to follow my arguments.

(14) Nopcsa, "The origin of flight," Proceedings of t he Zoological Society, 1907, I., p. 223.

(15) Abel, "Die Vorfohren der Vogel und ihre Lebensweise " (Verhandlungen der K.K. Zoologiscli -Botanischen Gesellschaf t in Wien Vol. LXI. of 1911, Parts 3, 4, 5, and 6 p. 144).

(16) Owen, "On the Archaeopteryx of Von Meyer " (Phil. Trans. of the Hoynl Society, Vol. 153 of 1863, p. 33). Hermann von Meyer, "Archaeopteryx lithographica " ( Palaeon tographica, Vol. X., 1861, p 53). Dames, " Ueber Archaeopteryx " (Palaeontologische Abhandlungen of Dames and Kayser, Vol. II., part 3, 1884).

(17) Pyecraf t, "The wing of Archaeopteryx " ( Natural Scfrncr , Vol. V., 1894, p. 351).

(18) Hankin, " A study of bird flight " ( Flight, August to December, 1912).