LITERATURE. 185 



VI. Archegosauria. — Vertebral column notochordal. Occipital 

 condyles unossified. 



23. Archegosaurus. 



B. Centra of dorsal vertebrce elongated, contracted in the middle — (Genera 

 24 to 31). 



VII. Heleothrepta. — Skull triangular, with a produced, tapering 

 snout. Orbits central. Mandibular symphysis very long, about 

 half the length of the skull. 



24. Lepterpeton. 



VIII. Nectridea. — Epiotic cornua much produced. Superior and 

 inferior processes of caudal A^ertebrae dilated at the extremities 

 and pectinate. 



25. Urocordylus. 



26. Keraterpeton. 



IX. AisTOPODA. — Limbs wanting. 



27. Ophiderpeton. 



28. Dolichosoma. 



X. MiCROSAURiA. — Thoracic plates unknown. Ossification of limb- 



bones incomplete. Dentine nearly or altogether non-plicate ; 

 pulp-cavity large. 



29. Dendrerpeton. 



30. Hylonomus. 



31. Hylerpeton. 



LITERATURE. 



1. Article " Amphibia." Huxley. ' Encyclopaedia Britannica.' 9th 



ed. 1875. 



2. " Ossemens fossiles." Cuvier. 4th ed. 1836. 



3. " Traite de Paleontologie." Pictet. 2d ed. 1853. 



4. "Odontography." Owen. 1840-45. 



5. " Manual of Palaeontology." Owen. 2d ed. 1861. 



6. " Fossil Reptilia discovered in the Coal-Measures of South Joggins, 



Nova Scotia." Owen. ' Quart. Journ. Geol. Soc.,' vol. xviii. 

 1862. 



7. " Acadian Geology." Dawson. 2d ed. 1867. 



8. " Air-breathers of the Coal-Period." Dawson. 1863. 



9. " New Labyrinthodonts from the Edinburgh Coal-field." Huxley. 



' Quart. Journ. Geol. Soc.,' vol. xviii. 1862. 



10. " Description of Vertebrate Remains from the Jarrow Colliery, 



Kilkenny. Huxley. ' Trans. Roy. Irish Academy,' vol. xxiv. 

 1867. 



11. " Vertebrate Fossils from the Panchet Rocks." Huxley. ' Palaeon- 



tologia Indica.' 1865. 



