Linnæan System
According to the system of Linnæus, the objects comprehended within the animal kingdom were divided into six classes: Mammalia or Mammiferous Animals, Birds, Amphibia or Amphibious Animals, Fishes, Insects, and Worms, which were thus distinguished:
Classes.
| Body | With vertebræ | Hot Blood | Viviparous | I. | Mammalia. |
| Oviparous | II. | Birds. | |||
| Cold red Blood | With lungs | III. | Amphibia. | ||
| With gills | IV. | Fishes. | |||
| Without vertebræ | Cold white Blood | Having antennæ | V. | Insects. | |
| Having tentacula | VI. | Worms. |