Orders: Ciliati (Rotifera), Denudati (Hydroids), Vaginati (Anthozoa and Polyzoa), Natantes (Crinoids).
Orders: Rotifera, Homogenea (this includes the Protozoa of recent writers and some Protophyta).
' Classes: Rotifera, Polygastria (the Protozoa of recent authors).
The Rotifera, the Chaetopoda and the Arthropoda.
Sub-phyla: Rotifera, Chaetopoda, Arthropoda.
This appears to indicate B that the Polyzoa are remotely allied to other phyla in which this type of larva prevails, and in particular to the Mollusca and Chaetopoda, as well as to the Rotifera, which are regarded as persistent Trochospheres.
ROTIFERA (or Rotatoria), a small, in many respects welldefined and somewhat isolated, class of the animal kingdom.
- Rotifera are unisexual, with the sexes dimorphic. The ovary is, as in many Platyhelminthes, duplex; one part, the germary, being an organ for the production by cell multiplication of the germ-cells or eggs.
The Rotifera are all aquatic, the majority dwelling in fresh water with Protozoa and Protophyta, as well as Entomostracous Crustacea.
Gosse, "Manducatory Organs in Class Rotifera," Phil.
C. Williamson, "The Rotifera" in A.
Jennings, Synopses of North American Invertebrates, xvii., "The Rotifera," Amer.
Quekett Club; C. Wesenberg-Lund, "Danmarks Rotifera," in Vid.
Most remarkable is its resemblance to the adult form of the Wheel animalcules, or Rotifera, which retain the prae-oral ciliated band as their chief organ of locomotion and prehension throughout life.
As in the Rotifera, it serves the veliger larva as an organ of locomotion.
And some Gephyrea; and the Rotifera appear to remain throughout life as modified Trochospheres.
The resemblance of Dinophilus to the Rotifera is, however, quite superficial, and the general structure of this genus with distinct traces of segmentation, especially in the embryo, points to its close affinity, if not to Polygordius in particular, at all events to the Annelida.
The animals thus associated, the Rotifera, Chaetopoda and Arthropoda, are composed of a larger or smaller number of hollow rings, each ring possessing typically a pair of hollow lateral appendages, moved by intrinsic muscles and penetrated by blood-spaces.
The Rotifera are characterized by the retention of what appears in Molluscs and Chaetopods as an embryonic organ, the velum or ciliated prae-oral girdle, as a locomotor and foodseizing apparatus, and by the reduction of the muscular parapodia to a rudimentary or non-existent condition in all present surviving forms except Pedalion.
- The characters of the subphylum and those of the associated sub-phyla Chaetopoda and Rotifera have been given above, as well as the general characters of the phylum Appendiculata which comprises these great sub-phyla.