"Order Aplacophora" belongs to a group of marine organisms that are worm-like and lack a calcium carbonate shell. Aplacophoran species are commonly referred to as "shell-less mollusks" and include various families such as Neomeniomorpha, Caudofoveata, and Chaetodermomorpha. Some popular synonyms associated with Aplacophoran species are shell-less mollusks, chitons, velvet worms, and worm-like mollusks. These creatures are found in different marine environments across the world and have unique morphological and ecological adaptations. Despite their peculiarities, Aplacophoran organisms play a crucial role in marine ecosystems and contribute to the diversity of marine fauna.