Here, linear arrangement has disappeared: there is a breaking up into groups and sub-groups and sub-sub-groups, which do not admit of being placed in serial order, but only in divergent and re-divergent order. Were there space to exhibit the way in which the Alliances are subdivided into Orders, and these into Genera, and these into Species, the same principle of co-ordination would be still further manifested.
| PHYLA. | SUB-PHYLA. | CLASSES. | SUB-CLASSES. | ALLIANCES. | ||||
| THALLOPHYTA |  | III. Schizophyta |  | 2. Cyanophyceæ. Blue-green Algæ. | ||||
| 3. Schizomycetes. | ||||||||
| III. Dinoflagellata Peridineæ | 4. | |||||||
| III. Bacillariales | 5. | |||||||
| IV. Gamophyceæ | III. Chlorophyceæ |  | 6. Protococcoideæ. | |||||
| 7. Siphoneæ. | ||||||||
| 8. Confervoideæ. | ||||||||
| 9. Conjugatæ. | ||||||||
| 10. Charales. | ||||||||
| 11. Phæophyceæ. | ||||||||
| 12. Dictyotales. | ||||||||
| 13. Florideæ, Red Seaweeds. | ||||||||
| IV. Fungi |  | III. Phycomycetes | | 14. Oomycetes. | ||||
| 15. Zygomycetes. | ||||||||
| III. Mesomycetes | | 16. | ||||||
| 17. | ||||||||
| III. Mycomycetes | | 18. | ||||||
| 19. | ||||||||
| Additional group of Fungi, Lichenes. | ||||||||
| ARCHEGONIATÆ |  | III. Bryophyta | | 20. Hepaticæ, Liverworts. | ||||
| 21. Musci, Mosses. | ||||||||
| III. Pteridophyta Vas. Cryptogams |  | 22. Filices, Ferns. | ||||||
| 23. Hydropterides, Rhizocarps. | ||||||||
| 24. Equisetales, Horse-tails. | ||||||||
| 25. Lycopodiales, Club-mosses. | ||||||||
| GYMNOSPERMÆ | | III. Cycadales, Cycads | 26. | |||||
| PHANEROGAMIA (Flowering Plants.) | | III. Coniferæ | 27. | |||||
| III. Gnetales | 28. | |||||||
| III. Monocotyledons | | 29. Liliifloræ. | ||||||
| 30. Scitamineæ. | ||||||||
| ANGIOSPERMÆ |  | 31. Gynandræ. | ||||||
| 32. Fluviales. | ||||||||
| 33. Spadicifloræ. | ||||||||
| 34. Glumifloræ. | ||||||||
 | 35. Centrospermæ. | |||||||
| 36. Protiales. | ||||||||
| 37. Daphnales. | ||||||||
| 38. Santalales. | ||||||||
| 39. Rafflesiales. | ||||||||
| III. Dicotyledons | | III. Monochlamydæ | 40. Asarales. | |||||
| 41. Euphorbiales. | ||||||||
| 42. Podostemales. | ||||||||
| 43. Viridifloræ. | ||||||||
| 44. Amentales. | ||||||||
| 45. Balanophorales. | ||||||||
| III. Monopetalæ | | 46. Caprifoliales. | ||||||
| 47. Asterales. | ||||||||
| 48. Campanales. | ||||||||
| 49. Ericales. | ||||||||
| 50. Vaccinales. | ||||||||
| 51. Primulales. | ||||||||
| 52. Tubifloræ. | ||||||||
| III. Polypetalæ |  | 53. Ranales. | ||||||
| 54. Parietales. | ||||||||
| 55. Malvales. | ||||||||
| 56. Discifloræ. | ||||||||
| 57. Crateranthæ. | ||||||||
| 58. Myrtales. | ||||||||
| 59. Melastomales. | ||||||||
| 60. Lythrales. | ||||||||
| 61. Hygrobiæ. | ||||||||
| 62. Passifloræ. | ||||||||
| 63. Pepones. | ||||||||
| 64. Cactales. | ||||||||
| 65. Ficoidales. | ||||||||
| 66. Umbellales. | ||||||||
On studying the definitions of these primary, secondary, and tertiary classes, it will be found that the largest are marked off from one another by some attribute which connotes sundry other attributes; that each of the smaller classes comprehended in one of these largest classes, is marked off in a similar way from the other smaller classes bound up with it; and that so, each successively smaller class has an increased number of co-existing attributes.
§ 100. Zoological classification has had a parallel history. The first attempt which we need notice, to arrange animals in such a way as to display their affinities, is that of Linnæus. He grouped them thus:[[42]]—
Cl. 1. MAMMALIA. Ord. Primates, Bruta, Feræ, Glires, Pecora, Belluæ, Cete.
Cl. 2. AVES. Ord. Accipitres, Picæ, Anseres, Grallæ, Gallinæ, Passeres.
Cl. 3. AMPHIBIA. Ord. Reptiles, Serpentes, Nantes.
Cl. 4. PISCES. Ord. Apodes, Jugulares, Thoracici, Abdominales.
Cl. 5. INSECTA. Ord. Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Diptera, Aptera.
Cl. 6. VERMES. Ord. Intestina, Mollusca, Testacea, Lithophyta, Zoophyta.