In 1890 Lydekker used the same classification, with minor changes, which he had used in his Paleontology. Credner, who wrote at about the same time (193), followed Zittel's classification. Zittel in 1895 merely repeated his former classification. In 1898 appeared Smith Woodward's Paleontology, where the following scheme is adopted: Class Batrachia. Order I. Stegocephalia. Order II. Gymnophiona. Suborder 1. Branchiosauria. Order III. Caudata. " 2. Aistopoda. Order IV. Ecaudata. " 3. Microsauria. " 4. Labyrinthodontia. Hay's Catalogue of Fossil Vertebrata of North America contains the next scheme for the classification of the Amphibia which pays especial attention to the extinct forms. His classification is as follows: Class Batrachia Macartney, 1802. Order Stegocephali Cope, 1868. Suborder Microsauria Dawson, 1863. Family _Protritonidæ_ Lydekker, 1889. Genera: _Amphibamus_ Cope, _Pelion_ Wym. Family _Molgophidæ_ Cope, 1875. Genera: _Phlegethontia_ Cope, _Molgophis_ Cope. Family _Hylonomidæ_ Fritsch, 1883. Genera: _Hylonomus_ Dawson, _Smilerpeton_ Dawson, _Hylerpeton_ Owen, _Fritschia_ Dawson; _Brachydectes_ Cope. Family _Ptyoniidæ_ Cope, 1875. Genera: _Keraterpeton_ Huxley, _Œstocephalus_ Cope, _Ptyonius_ Cope, _Ctenerpeton_ Cope. Family _Tuditanidæ_ Cope, 1875. Genera: _Tuditanus_ Cope, _Cocytinus_ Cope. Family _Diplocaulidæ_ Cope, 1881. Genus: _Diplocaulus_ Cope. Lepospondylous Genera of uncertain position: _Amblyodon_ Dawson, _Hyphasma_ Cope, _Eurythorax_ Cope, _Thyrsidium_ Cope, _Pleuroptyx_ Cope, _Cercariomorphus_ Cope. Suborder Apœcospondyli Hay, 1902. Family _Dendrerpetontidæ_ Fritsch, 1889. Genera: _Dendrerpeton_ Owen, _Baphetes_ Owen, _Platystegos_ Dawson. Family _Sauropleuridæ_ Hay, 1902. Genera: _Sauropleura_ Cope, _Leptophractus_ Cope. Family _Archegosauridæ_. Genera: _Trimerorhachis_ Cope, _Dissorophus_ Cope. Family _Cricotidæ_ Cope, 1884. Genera: _Cricotus_ Cope. Family _Anthracosauridæ_. Genus: _Eosaurus_ Marsh. Family _Eryopidæ_ Cope, 1882. Genera: _Eryops_ Cope, _Ichthycanthus_ Cope, _Zatrachys_ Cope, _Anisodexis_ Cope, _Acheloma_ Cope. Family _Mastodonsauridæ_ Huxley, 1863. Genera: _Mastodonsaurus_ Jaeger, _Eupelor_ Cope, _Pariostegus_ Cope, _Dictyocephalus_ Leidy. Order Urodela. Genera: _Scapherpeton_ Cope, _Hemitrypus_ Cope. Order Salientia Laurenti, 1768. Family _Ranidæ_. Genera: _Rana_ Linné, _Eobatrachus_ Marsh. This classification given by Hay is only for the forms which occur in North America. CHAPTER VII.