I. _Mastodonsaurus Jaeger._ (_Salamandroides_ Jaeger, _Batrachosaurus_ Fitzinger, _Labyrinthodon_ Owen.) _M. Jaegeri_ Meyer. II. _Capitosaurus_ Münster. _C. arenaceus_ Münst. _C. robustus_ Meyer. III. _Metopias_ Meyer. _M. diagnosticus_ Meyer. Three years later von Meyer (423) proposed his "System der fossilen Saurier," where the extinct Amphibia are treated as follows: Labyrinthodontes. 1. Prosthopthalmi (Augen-höhlen in der vordern Hälfte der Schädel-Länge) _Metopias_ Meyer Keuper. 2. Mesopthalmi (Augen-höhlen in der mitte der Schädel) _Mastodonsaurus_ Jaeger Keuper, Muschelkalk. 3. Opisthopthalmi (Augen-höhlen in der hintern Hälfte der Schädel-Länge) _Capitosaurus_ Münster Keuper. 4. Labyrinthodonten ungewisser Stellung. _Labyrinthodon_ Owen Keuper. _Xestorrhytias_ Meyer Muschelkalk. _Odontosaurus_ Meyer Bunter Sandstein. _Trematosaurus_ Braun Bunter Sandstein. No other classification was proposed for the extinct Amphibia for 15 years, when Owen (512) in 1859 proposed the new order Ganocephala and retained von Meyer's Labyrinthodontes under Labyrinthodontia. Owen's classification is as follows: Class--Reptilia. Order I. Ganocephala. Genera: _Archegosaurus_, _Dendrerpeton_, _Raniceps_. Order II. Labyrinthodontia. Genera: _Mastodonsaurus_, _Anisopus_, _Trematosaurus_, _Metopias_, _Capitosaurus_, _Zygosaurus_, _Xestorrhytias_. In his Paleontology published in 1861, Owen gives the same classification, but adds new genera. Huxley in 1863 (332) did not accept Owen's Ganocephala, but instead proposed the following: Labyrinthodontia. A. Archegosauria. _Archegosaurus_, _Pholidogaster_. B. Mastodonsauria. _Mastodonsaurus_, _Labyrinthodon_, _Capitosaurus_, _Trematosaurus_. In the same year Dawson proposed (208) the term Microsauria to include the genera _Hylonomus_, _Dendrerpeton_, and _Hylerpeton_, all known from the Carboniferous rocks of Nova Scotia. Two years later Cope proposed the new order Xenorhachia (105) for the reception of the form _Amphibamus grandiceps_ from the Coal Measures of Illinois. He gave as the characters of this order cartilaginous vertebræ and the absence of ribs. In 1866 Owen proposed (516) the most elaborate and comprehensive scheme of classification which had thus far been offered. His classification is as follows: