[89] _Sauropsida_--_sauros_, lizard; _opsis_, appearance. [90] Archœopteryx, see picture-heading, Chapter VII. [91] See picture-heading of this chapter. [92] _Ichthyornis_, fish-bird. [93] _Hesperornis._ [94] Some chamæleons and geckos also have air-tubes passing from the lungs into the body, and the crocodile’s skull is full of air-cells; but the two phenomena are not connected as in birds, and other parts of the skeleton or of the skin-covering, being heavy, have a counteracting effect. [95] This third eyelid is a fold on the inner side of the eye; some reptiles and amphibians have it, and so have the marsupials and many of the higher animals. [96] Struthio camelus. [97] Dinornidæ, of which Dinornis, a still more ancient form, must have been ten feet high. [98] This beautiful effect may be seen from below when the guillemots are fed in any of the public aquariums. [99] Talegallus. [100] Megapodidæ or large-footed birds. [101] Partridges, quails, and some others are exceptions, and pair. [102] Columba migratoria. [103] Gecinus viridis. [104] Alcedo ispida. [105] The Indian and Chinese edible-nest Swiftlets (Collocalia), make their nests entirely of this saliva, and they are eaten by the natives. [106] Troglodytes parvulus. [107] Orthotomus sutorius. [108] _Marsupium_, a pouch. [109] Ornithorhynchus paradoxus. [110] Echidna hystrix. [111] Professor Owen has described a reptile from the Trias of Africa, and Professor Cope another from the Permian of Texas, both having characters closely resembling the Platypus. [112] This argument, which can only be stated very roughly here, must not be supposed to rest merely on the quadrate bone, though this is the easiest point to illustrate popularly. I am deeply indebted to Mr. W. Kitchen Parker for a whole flood of light thrown on these early forms, and only regret that I have neither skill nor space to do justice to his graphic illustration of a subject of which he is pre-eminently master. [113] Diprotodont. [114] The only exceptions to this are a tooth and a piece of a tusk of one of the ancient elephants, lately found in Australia, showing that a few straggling forms of mammalia probably reached that country in Tertiary times. [115] Macropus giganteus. [116] Hypsiprymnus penicillatus. [117] Dendrolagus. [118] Phascolomys. [119] Dasyurus. [120] Thylacinus. [121] Didelphis. [122] Cholœpus. [123] Mymecophaga. [124] Dasypus. [125] Megatherium. [126] Glyptodon. [127] Myrmecophaga jubata. [128] Tamandua. [129] For a few of these forms see the picture-heading, p. 209. [130] Coryphodon. [131] Paleotherium and Anoplotherium. [132] Xiphodon. [133] Eohippus. [134] Hyænarctos. [135] Cynodon. [136] Hyænodon and others. [137] Arctocyon. [138] Cynomys. [139] Spalacidæ. [140] Geomyidæ. [141] Myogale Pyrenaica. [142] Castor fiber. [143] Potamogale. [144] Myogale. [145] Soledon and one of the Shrews. [146] Pteromys Petaurista. [147] Galeopithecus volans.