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Oligochaeta (/ ˌ ɒ l ɪ ɡ ə ˈ k iː t ə,-ɡ oʊ-/) [1] is a subclass of soft-bodied animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms.
Food enters at the mouth. The pharynx acts as a suction pump; its muscular walls draw in food. In the pharynx, the pharyngeal glands secrete mucus. Food moves into the esophagus, where calcium (from the blood and ingested from previous meals) is pumped in to maintain proper blood calcium levels in the blood and food pH. From there the food ...
The pharynx (pl.: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food to the esophagus and air to the larynx.
Opisthopora is an order of mostly terrestrial worms. [1] [2]It is an order of the subclass Oligochaeta, which is distinguished by meganephridiostomal, male pores which open posteriorly to the last testicular segment. [3]
The body cavity immediately behind the mouth opening, known as the oral cavity (or cavum oris in Latin), [2] is also the first part of the alimentary canal, which leads to the pharynx and the gullet. In tetrapod vertebrates , the mouth is bounded on the outside by the lips and cheeks — thus the oral cavity is also known as the buccal cavity ...
The ultrastructure of chaetae is fundamentally similar for all taxa but there is vast diversity in chaetal morphology. [4] Moreover, chaetae bear precise characters for determination of species and taxonomic assessment.
In general, however, they possess a pair of jaws and a pharynx that can be rapidly everted, allowing the worms to grab food and pull it into their mouths. In some species, the pharynx is modified into a lengthy proboscis. The digestive tract is a simple tube, usually with a stomach part way along.
He is known for his taxonomic work on the Oligochaeta and for being a "world authority" on the subject. [1] [2] [3] He published in his field for nearly 60 years. [4] [5] His main focus was the morphology, physiology, taxonomy, and zoogeography of earthworms, a collection of which he donated to the National Museum of Natural History. [6]