APPENDIX 543 



Order 5. Rhynchocephalia.* 



Sub-Order i. Proterosauria (Proterosaurus ; Pa- 



Iceohatteria) . 



Sub-Order 2. Rhynchocephalia vera * (Sphe no- 

 don [Hatteria], the only living 

 representative of the Order). 

 Order 6. Squamata. 



Sub-Order I. Dolichosauria (Dolichosaurus). 

 Sub-Order 2. Pythonomorpha (Mosasaurus). 

 Sub-Order 3. Lacertilia (lizards). 

 Sub-Order 4. Ophidia (snakes). 

 Order 7. Dinosauria. 



Sub-Order I. Theropoda (Anchisaurus) . 

 Sub-Order 2. Sauropoda (Brontosaurus). 

 Sub-Order 3. Ornithopoda (Iguanodon; Stego- 



saurus). 

 Order 8. Crocodilia.* 



Sub-Order i. Parasuchia (Belodon). 



Sub-Order 2. Mesosuchia (Pelagosaurus; Teleo- 



saurus) . 

 Sub-Order 3. Eusuchia * (Thoracosaurus ; Croco- 



dilus; Alligator). 



Order 9. Pterosauria (Pterodactylus; Rhamporhyn- 

 chus). 



[As is indicated above by the difference in type the proc- 

 ess of extinction in the group of Reptilia has gone very 

 far, leaving but four isolated spots to be represented among 

 the living forms; (i) the Chelonia, essentially a modern 

 group, (2) the Rhynchocephalia, represented by a single 

 living species, (3) the last two Sub-Orders of the Squamata, 

 the lizards and snakes, and (4) a very few modern representa- 

 tives or the Crocodilia. In arrangements in which living forms 

 are alone taken into consideration, these are given as five 

 Orders; the lizards and snakes count as two; in the earlier 

 works Sphenodon was counted among the lizards, redr.cing 

 the number to four. The Orders, as thus arranged, are as 

 follows : Chelonia, Rhynchocephalia, Lacertilia f Ophidia, 

 Crocodilia.} 



Class IV. Aves. 



Order i. Saururae (Arch&opteryx; Laopteryx). 

 Order 2. Odontormae (Ichthyornis; Apatornis). 



