Reptilia
Collier's New Encyclopedia (1921)
reptiles; cold-blooded, oviparous, or ovoviviparous, vertebrate animals having the skin covered with scales or scutes; heart with two auricles, ventricular chamber incompletely divided. Respiration takes place by lungs, respiratory movements being slow and irregular. Intestinal tract and urogenital organs open into a common cloaca. Aristotle was the first naturalist who wrote on reptiles. Some progress in classification was made by Ray (1628- 1705) and Linnæus (1707-1778). Brongniart, in 1799, first recognized the characteristics by which the Batrachia differ from other reptiles and form a natural passage to the fishes. In 1863 in his Hunterian Lectures, Huxley adopted the term Sauroids for that division of the vertebrates which he afterward called Sauropsida. He divides the Reptilia into the following orders: Chelonia, Plesiosauria, Lacertilia, Ophidia, Ichthyosauria, Crocodilia, Dicynodontia, Ornithoscelida, and Pterosauria. Owen makes reptiles proper the highest of the five sub-classes into which he finally divided his Hematocrya with orders: Ichthyopterygia (extinct), Sauropterygia (extinct), Anomodontia (extinct), Chelonia, Lacertilia (with the extinct Mosasaurus), Ophidia, Crocolilia (with the extinct Teleosaurus and Strepsospondylus), Dinosauria (extinct), and Pterosauria (extinct). Professor Mivart divides the Reptilia into the following orders: Ichthyopterygia (extinct), Anomodontia (extinct), Dinosauria (extinct), Ornithosauria (extinct), Crocodilia, Rhynchocephalia, Sauropterygia, Lacertilia, Ophidia, and Chelonia. The first appearance of reptiles is believed to be indicated by remains of a marine Saurian (Eosaurus acadianus) of Carboniferous age. Proterosaurus is found in the Permian. In Mesozoic times the reptilian type appears in such variety and in such a high state of development that this era has been distinguished as the Reptilian Age. In the Trias large marine Saurians and Dinosaurs are met with; more gigantic forms were developed in the Jurassic period; and the class attained its highest culmination in the Chalk.
What Has Changed in the Last Century
Collier's in 1921 still treated Reptilia as a tidy class of "cold-blooded" scaly vertebrates, with the amphibians (Batrachia) only recently split off by Brongniart and the dinosaurs safely filed among the extinct orders. Modern cladistics has dissolved that class as the old writers understood it: birds descend from theropod dinosaurs, so a Reptilia that excludes them is not a natural group, and the feathered dinosaur fossils found in Liaoning, China from the 1990s onward made the link vivid. Dinosaurs themselves are no longer read as sluggish sprawling saurians but as active, often warm-blooded animals, and their end is now tied to the Chicxulub impact 66 million years ago, identified off Yucatan in 1990-91. Genetics has also rearranged the branches, placing turtles (the old Chelonia) closer to crocodiles and birds than to lizards and snakes.
Written for this edition, 2026.