Feeding ecology and diet

Kinorhynchs are herbivorous and detrivorous. Most cy-clorhagids are diatom-feeders. They collect pennate diatoms using their rigid articulated oral styles as multiple pincers to locate one end of the shell and manipulate the diatom to their terminal mouth. Kinorhynchs bring diatoms into their buccal cavity with an action of their mobile buccal styles and with pumping movements of their sucking pharynx. The sharp buccal styles then move against the diatom, damaging the girdle and causing the two valves to separate. The diatom cell is emptied by the sucking of the pharynx, and the emptied frustule is rejected in the substrate. Echinoderes also can strip off terminal spines and collect diatoms between their head scalids. The diatoms are then collected by the oral styles using a repetitive withdrawing of the scalids and a protrusion of the mouth cone.

Most homalorhagids are selective deposit-feeders. They have flexible nonarticulated oral styles, which they use to collect detritus and bacterial clots. The sharp buccal teeth of the eversible anterior part of the buccal cavity also act as scrapers to graze on bacterial film and fungi.

Numerous glands secrete mucus, which is released onto the trunk surface. This secretion is also used to entrap detritus, bacteria, diatoms, and fungi, which are subsequently browsed on together with the mucus. Flexible and spiny cy-clorhagids also can strip off terminal spines and collect attached diatoms between their head scalids. The diatoms are then collected by the oral styles using a repetitive withdrawing of the scalids and a protrusion of the mouth cone.

The parasitic protozoan Kinorhynchospora japĆ³nica (phylum Microspora) infects all midgut cells of Kinorhynchus yushini. Sulfur gram-negative bacteria are found in a few special midgut cells (bacteriocytes) of Pycnophyes kielensis from the intertidal mud with sulfuretted hydrogen and are thought to be symbiotic.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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