INVERTEBRATE ZOOLOGY - H. I. Shcherbak - 2008

KINGDOM MULTICELLULAR ANIMALS (METAZOA)

SUBKINGDOM TRUE MULTICELLULAR ANIMALS (EUMETAZOA)

DIVISION TRIPLOBLASTIC (TRIPLOBLASTICA) OR BILATERAL (BILATERIA) ANIMALS

SUBDIVISION SPIRALIA (SPIRALIA)

PHYLUM FLATWORMS (PLATHELMINTHES)

SUBPHYLUM TURBELLARIANS (TURBELLARIA) OR ARCHIDERMATA

SUPERCLASS ARCHOPHORA (ARCHOPHORA)

CLASS CATENULIDA (CATENULIDA)

Predominantly small freshwater worms inhabiting Algae and Sphagnum moss. The Mouth, equipped with a Pharynx, is located near the anterior end of the body, and the intestine is sac-like. Catenulids possess a statocyst and ciliated pits, differing from other turbellarians by having a single protonephridial canal and the copulatory organ positioned on the DORSAL SIDE OF the body. They feed on small animals, mainly Ciliates and rotifers. Capable of asexual reproduction by transverse fission, where the anterior end of the new individual begins to form even before it detaches; subsequent divisions follow, and chains of 4–16 individuals can frequently be observed (Fig. 116). With the onset of cold weather, the animals reproduce sexually. A representative of this Class is Stenostomum tenuicauda.

Fig. 116. Stenostomum tenuicauda (from Ioffe):

1 - ciliated pits; 2 - pharynx; 3 - intestine



Last update: 13/08/2026

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