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P Kamptozoa (Entoprocta)





Overview & Classification




Biogeographic Distribution

Physical Characteristics

External Features

Internal Features

Biology & Behaviour

Reproduction & Development

Nutrition, Transport & Excretion

Predation & Disease

Climate Change

Evolution & Systematics

Diversity & Identification



Acknowledgments, References & Additional Notes

Physical Characteristics - Internal Features

As pseudocoelomate* organisms, the external body wall is made of a thin secreted cuticle and an underlying epidermis covered in microvilli. Underlaying and supporting the epidermis is a basal membrane and dense connective tissue, which can be found from the tips of the tentacles to the base of the stalk and foot. The body cavities are made of small interconnected fluid-filled hemocoels.

The body is made of a complete U-shaped gut, with mouth, oesophagus, stomach, intestine, rectum and anus, all covered in microvilli for transport of particles in and out of the system (see Nutrition, Transport & Excretion). The system is able to be closed by two circular sphincters found in the mouth and anus.

A distinctive characteristic of kamptozoans is the use of protonephridia for excretion, made of multiciliated terminal cells open into the atrium (see Nutrition, Transport & Excretion). Freshwater species, living in a hyposmotic* environment, have protonephridia along their stalk.

Nerves extend from paired ganglion found between the stomach and the atrium to the tentacles, calyx and stalk, where multiple receptors are present.

The gonads, single or paired, of the species are found between the stomach and atrium along a common gonoduct, which opens into the atrium (see Reproduction & Development).



Hyposmotic: said of a environment (here external) with a lower osmotic pressure than that of the internal environment of the organism.
Pseudocoelomate: said of an organism which exhibits some organisation of its tissues, but lacks a ‘true’ tripartite coelom.