The only exceptions we are aware of are some members of Oweniidae and possibly Magelonidae; larvae of these species bear at least some simple cilia arising from monociliated epidermal cells (Emlet and Strathmann, 1994; Bartolomaeus, 1995; Smart and von Dassow, 2009).
Secondary monociliarity in the Annelida: monociliated epidermal cells in larvae of Magelona mirabilis.
Its apical surface is occupied by cell bodies of perito-neocytes, monociliated
epithelial cells, connected to each other via intercelluar junctions (zonula adhaerense and septate junctions).
Roosen-Runge (1967) carefully observed the gastrovascular system of Phialidium medusae (Hydroidolina: Leptothecata) and found that simultaneously bidirectional flow (velocity 100 [micro]m/s) is driven by monociliated cells despite the very narrow canals (25 [micro]m in diameter).
Electron micrographs revealed that the entire gastrovasculature was lined with monociliated endodermal cells (with each cilium surrounded by a circlet of microvilli).
A remarkable feature of the mitraria is that the apparent homologs of the prototroch, metatroch, and food groove consist of monociliated cells (Emlet and Strathmann, 1994).
also possess deuterostome-like epidermis and nephridia, a conclusion based on the fact that monociliated cells dominate both tissues (Gardiner, 1978; Smith et al., 1987).
These species form coeloblastulae composed of monociliated
The larval photoreceptors are presumed to be a posterior ring of columnar monociliated
epithelial cells that possess 120-[micro]m-long cilia and pigment-filled protrusions.
Other features often used to categorize gastrotrichs--cross-striated muscles (Travis, 1983), monociliated
epidermis (Rieger, 1976), triradiate myoepithelial pharynx (Schmidt-Rhaesa et al., 1998), and bilayered nature of the cuticle (Schmidt-Rhaesa et al., 1998)--are plesiomorphies and, therefore, of limited systematic value.
cells make up the tentacular ciliary bands in pterobranchs, brachiopods, and phoronids, but bryozoans have multiciliated cells.
These are T-shaped monociliated
cells with a long vibratile cilium (Fig.