The History of Creation, Vol. 2 (of 2) / Or the Development of the Earth and its Inhabitants by the Action of Natural Causes - Ernst Haeckel

SYSTEMATIC VIEW
Of the 4 Classes and 30 Orders of the Animal Plants, or Zoophytes.
Class of the Zoophytes.	Legions of the Zoophytes.	Orders of the Zoophytes.		A Genus Name as example.
I. Sponges Spongiæ or Porifera	I. Myxospongiæ Mucous Sponges	1.	Archispongina	Archispongia
	I. Myxospongiæ Mucous Sponges	2.	Halisarcina	Halisarca
	II. Fibrospongiæ Fibrous Sponges	3.	Chalynthina	Spongilla
		4.	Geodina	Ancorina
		5.	Hexactinella	Euplectella
	III. Calcispongiæ Calcareous Sponges	6.	Ascones	Olynthus
		7.	Leucones	Dyssycus
		8.	Sycones	Sycurus
II. Corals Coralla or Anthozoa	IV. Tetracoralla Fourfold Corals	9.	Rugosa	Cyathophyllum
	IV. Tetracoralla Fourfold Corals	10.	Paranemeta	Cereanthus
	V. Hexacoralla Sixfold Corals	11.	Cauliculata	Antipathes
		12.	Madreporaria	Astræa
		13.	Halirhoda	Actinia
	VI. Octocoralla Eightfold Corals	14.	Alcyonida	Lobularia
		15.	Gorgonida	Isis
		16.	Pennatulida	Veretillum
III. Jelly-polyps Hydromedusæ or Hood-jellies Medusa	VII. Archydræ Primæval Polyps	17.	Hydraria	Hydra
	VIII. Leptomedusæ Soft Jelly-fish	18.	Vesiculata	Sertularia
		19.	Ocellata	Tubularia
		20.	Siphonophora	Physophora
	IX. Trachymedusæ Hard Jelly-fish	21.	Marsiporchida	Trachynema
		22.	Phyllorchida	Geryonia
		23.	Elasmorchida	Charybdæ
	X. Calycozoa Stalked Jellies	24.	Podactinaria	Lucernaria
	XI. Discomedusæ Disc-jellies	25.	Semæostomeæ	Aurelia
	XI. Discomedusæ Disc-jellies	26.	Rhizostomeæ	Crambessa
IV. Comb-jellies Ctenophora	XII. Eurystoma Wide-mouthed	27.	Beroida	Beroe
	XIII. Stenostoma Narrow-mouthed	28.	Saccata	Cydippe
		29.	Lobata	Eucharis
		30.	Tæniata	Cestum

PEDIGREE OF ZOOPHYTES

		Ctenophora					Hydromedusæ
		Tæniata	Lobata				Rhizostomeæ
		│ │	│ │				│ │
		Saccata Stenostoma					Semæostomeæ Discomedusæ
		│		Trachymedusæ			│	Siphonophora
		│		│			│	│
		Eurystoma		│ │	Lucernaria Calycozoa		│ │	│ │
		│ │		│ │	│ │		│ │	│ │
		│		│	│		│	│

		Leptomedusæ
				Coralla		│
				Hexacoralla	Octocoralla	│
				│	│	│
						│
				Tetracoralla		│
Spongiæ					│	│
Fibrospongiæ			Calcispongiæ		│	│
Chalynthina			Leucones	Sycones	│	│
Hexactinella	│	Geodina	Dyssycus	Sycurus	│	Hydroida
│	│	│	│	│	│	│	Cordylophora
│	│	│	│	│	│	│	│	Hydra
					│	│	│	│
│			Ascones		│	│	│	│
│ │	Myxospongia Halisarcina		│ │		│ │	Hydroida
Chalynthus	│		Olynthus		│	│
│	│		│		│	│
Archispongiæ					Hydroida
	│			│
	│			Archydra
	│			│
Protascus
│
Gastræa

The second class of Sea-nettles is formed by the Hood-jellies (Medusæ) or Polyp-jellies (Hydromedusæ). While most corals form stocks like plants, and are attached to the bottom of the sea, the Hood-jellies generally swim about freely in the form of gelatinous bells. There are, however, numbers of them, especially the lower forms, which adhere to the bottom of the sea, and resemble pretty little trees. The lowest and simplest members of this class are the little fresh-water polyps (Hydra and Cordylophora). We may look upon them as but little changed descendants of those Primæval polyps (Archydræ), from which, during the primordial period, the whole division of the Sea-nettles originated. Scarcely distinguishable from the Hydra are the adherent Hydroid polyps (Campanularia, Tubularia), which produce freely swimming medusæ by budding, and out of the eggs of these there again arise adherent polyps. These freely swimming Hood-jellies are mostly of the form of a mushroom, or of an umbrella, from the rim of which many long and delicate tentacles hang. They are among the most beautiful and most interesting inhabitants of the sea. The remarkable history of their lives, and especially the complicated alternation of generation of polyps and medusæ, are among the strongest proofs of the truth of the theory of descent. For just as Medusæ still daily arise out of the Hydroids, did the freely swimming medusa-form originally proceed, phylogenetically, out of the adherent polyp-form. Equally important for the theory of descent is the remarkable division of labour of the individuals, which among some of them is developed to an astonishingly high degree, more especially in the splendid Siphonophora.[(37)] (Plate [VII]. Fig. 13).

The third class of Sea-nettles—the peculiar division of Comb-jellies (Ctenophora), probably developed out of a branch of the Hood-jellies. The Ctenophora, which are also called Ribbed-jellies, possess a body of the form of a cucumber, which, like the body of most Hood-jellies, is as clear and transparent as crystal or cut glass. Comb or Ribbed-jellies are characterized by their peculiar organs of motion, namely, by eight rows of paddling, ciliated leaflets, which run in the form of eight ribs from one end of the longitudinal axis (from the mouth) to the opposite end. Those with narrow mouths (Stenostoma) probably developed later out of those with wide mouths (Eurystoma). (Compare Plate [VII]. Fig. 16.)

The third tribe of the animal kingdom, the phylum of Worms or worm-like animals (Vermes, or Helminthes), contains a number of diverging branches. Some of these numerous branches have developed into well-marked and perfectly independent classes of Worms, but others changed long since into the original, radical forms of the four higher tribes of animals. Each of these four higher tribes (and likewise the tribe of Zoophytes) we may picture to ourselves in the form of a lofty tree, whose branches represent the different classes, orders, families, etc. The phylum of Worms, on the other hand, we have to conceive as a low bush or shrub, out of whose root a mass of independent branches shoot up in different directions. From this densely branched shrub, most of the branches of which are dead, there rise four high stems with many branches. These are the four lofty trees just mentioned as representing the higher phyla—the Echinoderma, Articulata, Mollusca, and Vertebrata. These four stems are directly connected with one another at the root only, to wit, by the common primary group of the Worm tribe.