Definition: The term "Achetidae" is a genus in the order Ctenophora within the class Annelida. Definition of Achetidae: Acetidae is the order of ctenophores, a group of aquatic insects with flat bodies covered with long spines that form a variety of shapes. They are typically found in saltwater and have an open gills on their bodies, which allows them to breathe through the water they swim in. The genus "Achetidae" contains 15 species of ctenophores in the order Acetidae. Some notable members of this group include: 1. Achetus: This genus is characterized by its large, flat body covered with long spines and a wide range of shapes. It has an open gill on its body. 2. Alitobius: Another genus that belongs to the order Acetidae. These species are known for their long, thin bodies covered with hard spines. 3. Ancephalus: This genus includes a variety of aquatic insects known as ctenophores. Some common examples include A. gomus (the common alitobius), A. dactylifera (the common ancephalus), and A. japonicus (the Japanese alitobius). 4. Acanthocephala: This genus includes a group of ctenophores characterized by their flattened bodies covered with long spines. Some examples include A. ancas, A. agamemnon, and A. leucophasia. 5. Acanthocyclus: This genus includes ctenophores characterized by their flat bodies covered with long spines and a narrow gill. 6. Anctosoma: This genus is characterized by its flattened bodies covered with long spines and an open gill on its body. 7. Acatycephala: This genus includes a group of aquatic insects known as ctenophores. Some common examples include A. acatycephala, A. caeciliifera, and A. cyprinoides. 8. Acanthocysteae: This genus includes ctenophores characterized by their flat bodies covered with long spines and an open gill on its body. The specific names of species in this order include the common names of these animals, as well as the scientific name used for them.

Achetidae