L. C. Miall — On Lahyr'intJiodonta. 513 



tliis species is found in zones 4 and 5 ; and Z. Keijserlingi only 

 in zone 5, The true L. Balthica is confined to Central Gothland. 

 In Eussia the limestones with smooth Pentameri contain Z. marginata ; 

 and in Siberia Z. Wiluiensis, L. par-allela, and IsocMlina Maald. 

 Leperditia Eicliwaldi is met with between zones 7 and 8. In some 

 localities Z. Angelini is one of the most numerous of the fossils. Z. 

 grandis has been found near Liimmada, together with Z. Angelini, 

 and in the Uppermost Silurian of the Isle of Gotliland. The same 

 strata, with Z. Tyraica (a form comparable with the American Z. 

 alta of Conrad), exist along the Dnieper in Volhynia and Podolia. 



IsocMlina Biensis has been met with near Slatoust in the Upper 

 Silurian, with Pentamerus Baschlciricus ; and Zeperditia Barbotana 

 at a somewhat more northern locality, in a rock with Leper ditice 

 only. ^ T. K. J. 



II. — Tabular. View of the Classification of the Labyeintho- 

 DONTA.^ By L. C. Miall. 



AMPHIBIA. 



LABYRINTHODONTA. 

 A. — Centra of dorsal vertehrce discoidaU — Genera 1 to 27. 

 I. — EuGLYPTA. Cranial bones strongly sculptured. Lyra con- 

 spicuous-. Mandible with well-developed post-articular process. 

 Teeth conical ; their internal structure complex ; dentine much 

 folded. Palato-vomerine tusks in series with small teeth. Short 

 inner series of mandibular teeth. Sculptured thoracic plates, with 

 reflected process upon the external border. 

 * Palatine foramina large, approximated. 



■f Mandible with an internal articular buttress. 

 I Orbits central or posterior. 



1. Mastodonsaurus, Jager. 



2. Capitosaurus, Munst. 



3. Pachygonia, Huxley (?). 



4. Eurosaurus, d'Eichwald (?). 



5. Trematosaurus, Braun. 



6. Gonioglyptus, Huxley. 

 ^1 Orbits anterior. 



7. Metopias, Von Meyer. 



8. Labyrinthodon, Owen.' 



ff Mandible without internal articular buttress. 



9. Diadetognathus, Miall. 

 **•' Palatine foramina small, distant. 



10. Dasyceps, Huxley. 



11. Anthracosaurus. Huxley. 



II. — Brachtopida. Skull parabolic. Orbits oval, central or 

 anterior. Post-articular process of mandible wanting (?). 



^ Presented to the Geological Section of the British Association at Belfast, August, 

 1874, by the Committee on the Labyrinthodonts of the Coal Measures. 



2 This character is not of primary importance, but seems to be available for an 

 arrangement determined by other considerations. 



3 Orbits unknown. 



DECADE II. — VOL. I. NO. XI. 33 



