Page:An Introduction to the Study of Fishes.djvu/49

Rh {| style="width: 90%;" align="center"
 * colspan="4" align="center" | Sub-classis III.—Ganoidei.
 * colspan="4" align="center" | Ordo I.—Holostei.
 * || align="right" | Fam. 1. || Lepidosteini.
 * || align="right" | "&#160;&#160;&#160;2. || Polypterini.
 * colspan="4" align="center" | Ordo II.—Chondrostei.
 * || align="right" | Fam. 1. || Acipenserini.
 * || align="right" | "&#160;&#160;&#160;2. || Spatulariæ.
 * colspan="4" align="center" | Sub-classis IV.—Elasmobranchi s. Selachii.
 * colspan="4" align="center" | Ordo I.—Plagiostomi.
 * colspan="4" align="center" | Sub-ordo I.—Squalidæ.
 * align="right" | Fam. 1. || Scyllia. || align="right" | Fam. 6. || Rhinodontes.
 * align="right" | "&#160;&#160;&#160;2. || Nyctitantes. || align="right" | "&#160;&#160;&#160;&#160;7. || Notidani.
 * align="right" | "&#160;&#160;&#160;3. || Lamnoidei. || align="right" | "&#160;&#160;&#160;&#160;8. || Spinaces.
 * align="right" | "&#160;&#160;&#160;4. || Alopeciæ. || align="right" | "&#160;&#160;&#160;&#160;9. || Scymnoidei.
 * align="right" | "&#160;&#160;&#160;5. || Cestraciones. || align="right" | "&#160;&#160;10. || Squatinæ.
 * colspan="4" align="center" | Sub-ordo II.—Rajidæ.
 * align="right" | Fam. 11. || Squatinorajæ. || align="right" | Fam. 14. || Trygones.
 * align="right" | "&#160;&#160;&#160;12. || Torpedines. || align="right" | "&#160;&#160;15. || Myliobatides.
 * align="right" | "&#160;&#160;&#160;13. || Rajæ. || align="right" | "&#160;&#160;16. || Cephalopteræ.
 * colspan="4" align="center" | Ordo II.—Holocephali.
 * || align="right" | Fam. 1. || Chimaeræ.
 * colspan="4" align="center" | Sub-classis V.—Marsipobranchii s. Cyclostomi.
 * colspan="4" align="center" | Ordo I.—Hyperoartii.
 * || align="right" | Fam. 1. || Petromyzonini.
 * colspan="4" align="center" | Ordo II.—Hyperotreti.
 * || align="right" | Fam. 1. || Myxinoidei.
 * colspan="4" align="center" | Sub-classis VI.—Leptocardii.
 * colspan="4" align="center" | Ordo I.—Amphioxini.
 * || align="right" | Fam. 1. || Amphioxini.
 * }
 * align="right" | "&#160;&#160;&#160;4. || Alopeciæ. || align="right" | "&#160;&#160;&#160;&#160;9. || Scymnoidei.
 * align="right" | "&#160;&#160;&#160;5. || Cestraciones. || align="right" | "&#160;&#160;10. || Squatinæ.
 * colspan="4" align="center" | Sub-ordo II.—Rajidæ.
 * align="right" | Fam. 11. || Squatinorajæ. || align="right" | Fam. 14. || Trygones.
 * align="right" | "&#160;&#160;&#160;12. || Torpedines. || align="right" | "&#160;&#160;15. || Myliobatides.
 * align="right" | "&#160;&#160;&#160;13. || Rajæ. || align="right" | "&#160;&#160;16. || Cephalopteræ.
 * colspan="4" align="center" | Ordo II.—Holocephali.
 * || align="right" | Fam. 1. || Chimaeræ.
 * colspan="4" align="center" | Sub-classis V.—Marsipobranchii s. Cyclostomi.
 * colspan="4" align="center" | Ordo I.—Hyperoartii.
 * || align="right" | Fam. 1. || Petromyzonini.
 * colspan="4" align="center" | Ordo II.—Hyperotreti.
 * || align="right" | Fam. 1. || Myxinoidei.
 * colspan="4" align="center" | Sub-classis VI.—Leptocardii.
 * colspan="4" align="center" | Ordo I.—Amphioxini.
 * || align="right" | Fam. 1. || Amphioxini.
 * }
 * || align="right" | Fam. 1. || Chimaeræ.
 * colspan="4" align="center" | Sub-classis V.—Marsipobranchii s. Cyclostomi.
 * colspan="4" align="center" | Ordo I.—Hyperoartii.
 * || align="right" | Fam. 1. || Petromyzonini.
 * colspan="4" align="center" | Ordo II.—Hyperotreti.
 * || align="right" | Fam. 1. || Myxinoidei.
 * colspan="4" align="center" | Sub-classis VI.—Leptocardii.
 * colspan="4" align="center" | Ordo I.—Amphioxini.
 * || align="right" | Fam. 1. || Amphioxini.
 * }
 * colspan="4" align="center" | Ordo II.—Hyperotreti.
 * || align="right" | Fam. 1. || Myxinoidei.
 * colspan="4" align="center" | Sub-classis VI.—Leptocardii.
 * colspan="4" align="center" | Ordo I.—Amphioxini.
 * || align="right" | Fam. 1. || Amphioxini.
 * }
 * colspan="4" align="center" | Sub-classis VI.—Leptocardii.
 * colspan="4" align="center" | Ordo I.—Amphioxini.
 * || align="right" | Fam. 1. || Amphioxini.
 * }
 * || align="right" | Fam. 1. || Amphioxini.
 * }

The discovery (in the year 1871) of a living representative of a genus hitherto believed to be long extinct, Ceratodus,