{98}The Anseres or Natatores are almost equally unsettled. The flamingoes are usually placed in this order, but their habits best assort with those of the waders. Fam. 118. Anatidæ Duck and Geese. 119. Laridæ Gulls. 120. Procellariidæ Petrels. 121. Pelecanidæ Pelicans. 122. Spheniscidæ Penguins. 123. Colymbidæ Divers. 124. Podicipidæ Grebes. 125. Alcidæ Auks. The last order of birds is the Struthiones or Ratitæ, considered by many naturalists to form a distinct sub-class. It consists of comparatively few species, either living or recently extinct. Fam. { 126. Struthionidæ Ostriches. Living { 127. Casuariidæ Cassowaries. { 128. Apterygidæ Apteryx. { 129. Dinornithidæ Dinornis. Extinct { 130. Palapterygidæ Palapteryx. { 131. Æpyornithidæ Æpyornis. REPTILES. In reptiles I follow the classification of Dr. Günther as given in the _Philosophical Transactions_, vol. clvii., p. 625. He divides the class into five orders as follows:-- Sub-classes. Orders. { 1. Ophidia Serpents. I. Squamata { 2. Lacertilia Lizards. { 3. Rhyncocephalina The Hatteria. II. Loricata 4. Crocodilia Crocodiles. III. Cataphracta 5. Chelonia Tortoises. In the arrangement of the families comprised in each of these orders I also follow the arrangement of Dr. Günther and Dr. J. E. Gray, as given in the British Museum Catalogue, or as modified by the former gentleman who has kindly given me much personal information. {99}The Ophidia, or Snakes, form the first order and are classified as follows:-- Fam. { 1. Typhlopidæ } { 2. Tortricidæ } { 3. Xenopeltidæ } Burrowing Snakes. { 4. Uropeltidæ } { 5. Calamaridæ Dwarf ground-snakes. { 6. Oligodontidæ. { 7. Colubridæ Colubrine Snakes. { 8. Homalopsidæ Fresh-water Snakes. { 9. Psammophidæ Desert-snakes. Innocuous Snakes { 10. Rachiodontidæ. { 11. Dendrophidæ Tree-snakes. { 12. Dryiophidæ Whip-snakes. { 13. Dipsasidæ Nocturnal tree-snakes. { 14. Scytalidæ { 15. Lycodontidæ Fanged ground-snakes. { 16. Amblycephalidæ Blunt-heads. { 17. Pythonidæ Pythons. { 18. Erycidæ Sand-snakes. { 19. Acrochordidæ Wart-snakes.