114. Natural System (Jussieu’s).

Classes.
I.Acotyledons1stClass.
II.Monocotyledons
Mono-hypogynæ (stamens hypogynous)2nd
Mono-perigynæ (stamens perigynous)3rd
Mono-epigynæ (stamens epigynous)4th
III.Dicotyledons.
Monoclines, flowers hermaphrodite.
Apetalæ (no petals)
Epistamineæ (stamens epigynous)5th
Peristamineæ (stamens perigynous)6th
Hypostamineæ (stamens hypogynous)7th
Monopetalæ (petals united).
Hypocorollæ (corolla hypogynous)8th
Pericorollæ (corolla perigynous)9th
Epicorollæ (corolla epigynous)Synantheræ (anthers united)10th
Chorisantheræ (anthers free)11th
Polypetalæ (petals distinct)
Epipetalæ (petals epigynous)12th
Peripetalæ (petals perigynous)13th
Hypopetalæ (petals hypogynous)14th
Diclines, flowers unisexual, or without a perianth.15th

This system, being likewise founded partly on individual organs, is also, to a certain extent, artificial; and, strictly speaking, every natural method of botanic classification must partake more or less of an artificial character, as many orders of plants merge so insensibly into others that their respective limits cannot be accurately or rigorously defined.


CHAPTER LIV.
ZOOLOGY.

CLASSIFICATION OF ANIMALS—VERTEBRATES AND INVERTEBRATES—PROTOZOA—HYDROZOA—ACTINOZOA.

Zoology treats of life—of organized beings which are capable of voluntary motion. Plants exist, animals live and move. Both are organic beings, but the latter possess the faculty of will and spontaneous movement. The animal can leave a place and enjoy other surroundings, the plant cannot. We have already crossed the borderland which connects the plant and the animal. We have seen plants almost animals. We could commence this section with animals which are almost plants, so closely do the divisions approach each other. Zoology is the science of the knowledge of animals as Botany is of the knowledge of plants.

Fig. 826.—Echinus, or Sea-Urchin.