3118. Would we compare these animals with the parts in plants, they then represent their cell-development, or cells, bark and root. They are themselves either vesicles, as the Infusoria, or barks, as the Corallines, or a root-like fascicle of tubes, as the Acalephæ.
3119. In the animals, however, the cells have become stomach, the bark intestine, the root absorbents. The Oozoa represent therefore the aggregate of the intestinal system, the primary mass of the animal body.
Their whole body is a digestive body, or parenchyma, traversed in many species in all directions by tubes or absorbents, as in the Acalephæ.
As yet no nervous filament, nor any muscular fibre, &c. has been separated from their mass, as in like manner a tegument has barely been freed or separated from the intestine. These animals are nerveless and sine-tegumental, precisely because they are wholly made up of nervous mass and tegument.
Circle II. Vascular Animals.
3120. In the next place the digestive separates completely from the tegumental function, and each constitutes a function for itself, but which now being separated from its fellow could no longer subsist. Between the two therefore is formed the nutritive function in the vascular system.
Now, the vascular system of the self-substantial intestine is the liver. This organ will therefore for the first time make its appearance in this animal circle—Hepatic animals. Upon a higher stage, salivary glands are also developed on the intestine, and will here likewise begin for the first time to appear—Salivary animals, Snails.
3121. Through the separation of the viscera from the remaining substance, this must necessarily remain behind as a hollow cyst or tegument investing the former. The true free tegumental formation is therefore by no means accidental, but is necessarily bestowed with the viscera in the course of animal development. This tegument is peritoneum. There are animals which are invariably bicystic, but consisting of concentric cysts—abdomens.
Around the ventral integument, however, the vascular system also forms its tunic; this is the branchial membrane or operculum—pleura, mantle. There are tri-cystic animals—intestine, abdomen, and thorax disposed concentrically around each other—Mussels. Their body is therefore not articulated, but its parts are still inserted within each other.
The Vascular animals are consequently multiplied Protozoa; or Mucus-animals of the second power—Ovum2.