There are about 6,500 species of turbellarians
worldwide (Schockaert et al.
However, in the Beagle Channel mussel populations, a metacercaria parasitizing the foot and byssus gland was found, which was absent in the specimens here studied; conversely, turbellarians
and copepods were absent in the Beagle Channel population (Cremonte et al.
The predatory turbellarian
studied here belongs to the monophyletic (Littlewood el at, 1999) suborder Kalyptorhynchia Graff, 1905 (Fig.
and nematodes were found in low densities.
The polyclad turbellarians
from the Philippine Islands.
The Mollusca: coelomate turbellarians
or mesenchymate annelids?
The non-productive fraction of the microbiota ("microfauna") consists of bacteria, diatoms, flagellates, and ciliates (3-328 ft [1-100 m]); the meiofauna (328-3,281 ft [100-1,000 m]) is rich in foraminifers, nematodes, turbellarians
, gastrotrichans, cumaceans, copepods, and the juvenile phases of macro-invertebrates.
Copepods and turbellarians
were fixed in 70% ethanol.
The ability to naturally reverse the direction of waveform propagation has been reported for the sperm of the polyclad turbellarians
Notoplana atomata, Polyposthia similis, and Leptoplana tremellaris (Hendelberg, 1965, 1983), the parasitic polychaete Myzostomum cirriferum (Afzelius, 1982, 1983), and the tephritid flies Ceretitis capitata, Dacus oleae, and D.
resembling a Urastoma sp.
On the geographical occurrence of pelagic polyclad turbellarians
The results showed the presence of rickettsiales-like organisms (RLO) in the epithelium of the digestive gland, ciliates, and unidentified coccidia in gills, a meront-like cell in one digestive gland, digenean trematode sporocysts in gonads, metacercariae embedded in the foot, and turbellarians
The highly stereotypic cleavage pattern referred to as "spiral cleavage" occurs in most of the extant invertebrate phyla, including the molluscs, annelids, vestimentiferans, pogonophorans, echiurans, sipunculids, nemerteans, gnathostomulids, mesozoans, and polyclad turbellarians
Two new rhabdocoel turbellarians
parasitic in Tasmanian holothurians.
Others invertebrates, however, move food around in a much slower manner: branching corals translocate nutrients to the tip of branches for tip growth (Buchsbaum Pearse and Muscatine, 1971); gorgonians have cells that travel through the stem canals and solenia, a collagenous filled mesohyl, to deliver nutrients to the other tissues of the animal (Murdoch, 1978); fixed parenchymal cells in turbellarians
are thought to act as a sort of stationary intracellular circulatory system (Pedersen, 1961); and acid phosphatase staining has shown that amebocytes in the hemal lacuna of crinoids (again, a collagen-filled pathway) are involved in digestion and transport of nutrients (Heinzeller and Welsch, 1997).