3468. Decomposition is a separation into Monads, a retrogression into the primary mass of the animal kingdom.
3469. All propagation, even that of the sex, commences like the animal kingdom, or with its first family. On that account the embryonic development must be a passage through the animal kingdom.
3470. The Rhizopoda usually adhere together within a multi-chambered calcareous shell, out of which they protrude mucous filaments, and are therefore the antetypes of the Corals or Polyps.
3471. The Rotifera exhibit all kinds of viscera, such as intestine and ovaries; besides what have been called rotatory organs, which remind us of the arms or tentacles of the Acalephæ.
3472. The families of these animals may be therefore aptly named as follows:
Fam. 1. Typical Infusoria—Monades; cilia or vibratile organs.
2. Polypary Infusoria—Rhizopoda; extensible processes.
3. Acalephan Infusoria—Rotifera; intestine and oral organs.
Second Class.
Intestinal, Albuminous Animals—Polypi.
3473. The Polyps also do not admit of being divided into more than three families. The first are only tubes or vesicles with capillary tentacula around the mouth, as the naked Polyps, Tubulariæ, Sertulariæ, and Cellulariæ.
The others have true ciliated tentacular rays surrounding the mouth, and are always condensed inferiorly into a horny, and occasionally stony axis or stem, as is seen in the Gorgoniæ, Alcyoniæ, and Isidiæ.