78 GUIDE TO THE FOSSIL REPTILES, AMPHIBIANS, FISHES. 
W all-case Europe, North America, and Australia. All these early 
5 - genera differ from the existing Dipnoi in having more 
Tab ia CaSe numerous bones in the roof of their skull. Teeth identical 
with those of the existing Australian Ceratodus (Figs. 79, 80) 
are known from the Trias and Rhaetic of Europe, India, 
and South Africa; from the Jurassic of Europe, North 
America, and Australia; and from the Cretaceous of Pata- 
Fig. 79.—The existing Australian Mud-fish (Ceratodus forsteri), from rivers 
in Queensland; much reduced in size. 
Fig. 80.—Mouth of Ceratodus forsteri; about one-half nat. size. nn. 
narial openings ; x. vomerine teeth ; xx. palato-pterygoid teeth ; xxx. 
mandibular teeth. 
gonia and Northern Africa. A skull which is more exten¬ 
sively ossified and otherwise slightly different from that of 
the existing Ceratodus was obtained by the Geological 
Survey of Austria from the Rhaetic of that country. A 
typical collection of teeth from the Rhaetic of Aust Cliff, 
near Bristol, and from the Trias of England, Wiirtemberg, 
India, and South Africa, is exhibited in Table-case 10. 
